I've been refreshing the channel to check for updates and finally a new vid! :D An incredible amount of information, as always. Also, with regards to pathogens, will there be any videos in the future about methods to deal with the different types of pathogen/pests? I am currently following your blog posts for the 'grape juice'/neem oil/garlic sprays and I was wondering if there will be any updates or instructional videos :) It feels like the many hobbyist/small-scale farmers around my place just use too many toxic pesticides and I would love to recommend something less harmful. Thank you!
How do you add the hypochlorous acid to the reservoirs? I add it first before any nutrients. But don't the nutrients affect the hypochlorous acid content once they are added, should you add another dose of hypochlorous acid after nutrients are added? I cant seem to get the free chlorine reading on the test strips after the nutrients are added. When I test before the nutrients are added, I get a very clear 2 ppm result.
Thanks for commenting. The nutrients have several things that are oxidized quickly by chlorine, mainly ferrous iron. You should add hypochlorite or hypochlorous acid after you add nutrients and get the free chlorine reading then.
The UV light will damage organic molecules (like chelates) if the exposure times are too long. For this reason UV light should only be used in line with pumps so that water is sanitized right before irrigation, it should not be permanently shone on the solution nor the solution permanently recirculated through a UV light. The pass through to the UV light should be only done once, when water flows to the plants. In this amount of time, chelate destruction is minimal.
Great content as always....Love from India. I have a small clarification, instead of directly installing uv filters in the line of irrigation line, can we install in the pump backflow line? In my case, we use a huge pump of 36m3/hr , whereas pump has a backflow around 5 m3/hr. Can I install Uv across this backflow and help us in controlling pathogens? Looking forward to your response
Thanks for commenting! This is not ideal because contamination will occur after it goes through the UV filter, in the rest of the irrigation system. A UV system should always be placed as close as possible to the point of release to plants, to ensure maximum effectiveness. However a UV system anywhere will be better than doing nothing.
Great video! I have some questions on making HOCL. When it comes to making your own HOCL is it that you must PH the sodium hypochlorite to 5.8 exactly or can it go below 5.8 and still make the chemical change to HOCL. Also once you have adjusted your solution to 5.8 and made the HOCL can you then raise the PH of your solution without affecting the HOCL? Or will raising your PH from 5.8 negatively affect the HOCL in the solution.
When making your own HOCl, be careful with concentration. One thing is generating s very small amount of HOCl by adding a very small amount of bleach to a nutrient solution, a very different thing is to try to lower the pH of a concentrated bleach solution (dangerous as this generates chlorine gas). Never create HOCl solutions with a concentration higher than around 250 ppm. Any pH below around 7 will already imply all the hypochlorite converts to hypochlorous acid, anything in the 5.5-7 range is acceptable as far as HOCl goes.
I just made the HOCl solution based on your protocol. The master grower at the facility said that the athena cleanse smells very strong and their pH is very low (4) so he doesn’t believe my product is right 😅.
Fantastic video, as im sure your aware early hydroponicum researchers delivered solutions heated, either sanitation was an unforeseen benefit or intended purpose and don't recall what their reasoning was, just know it became discontinued practice. Was this due to addition of 2ppm chlorine?
Thanks for commenting! I don't recall early hydroponic researchers heating up solutions, so I'll need to discuss with some of my colleagues to verify this for you and answer the question.
Thank you I've been going through my research archives lately so perhaps will stumble across it in an update.. I do know there was bed heating done in colder climate pre WW2 as well cooling in hot such a middle east and India by U.S military and OIL CO outposts 30's -40's but this was related to other factors if I recall and think it's was earlier than that. My peak of interest never quite resolved was resulted from early patent searching and devices and stumbled across the solution heating and delivery mechanical patents was where it originated. If memory serves and it's a little slower now lol it was said to be scalding temp then cooled before addition. What I do know is it wasn't for distillation of which they did do to such a huge extent it was mind boggling. Another theory coming to mind they believed it somehow thought it kept a precipitation of FE from occuring l but can't recall what I read that leads to that thought that pops up now lol. If you come up short I'll update this for the historic reference if nothing else as now I'm preoccupied to figure it out. I'm a bit of a hydo history buff, it's so facinating as well the little known politics behind the scenes in those days that need to take into account reading the publications.. eg Hoagland speaking against all the sensationalism, downplaying the commercial and hobby aspects but here we are today what he spoke against is now fact and his formula the basis. Little known was the politics of Gericke vs the University Hoagland and Knopp at that writing. Thank you.
What would you recommend for a large DWC pond (cement pond) where the water is rarely replaced? In my experience, it is very difficult to add hypochorite because it reacts rapidly with plant roots making it seem like the concentration is not high (when testing with strips or titration), meanwhile I’ve almost killed an entire crop this way trying to reach a few ppm. Also, I worry about chloride buildup, or unwanted sodium or calcium. When I spoke to Dramm they recommend ozone systems saying that the oxygen biproduct makes you better off than you stated, and while I heard of chelate degradation and precipitation, these issues are less costly than pathogens. In my case it does not help me much to know my input water is clean, because the pond is constantly recirculating for a very long time. I have experienced root rot sometimes and need a way to knock down pathogens and something constant to make sure they do not return. In my case it is not feasible to sanitize a pond for very long.
Thanks for commenting. In your case, putting an inline UV system right after your pump would be the most effective solution to keep your solution sanitized. This way we really don't care about pathogens in the pond, but just ensure that anything that is fed to plants is sanitized. Adding a 50% excess of chelating agent would also help maintain a chelate reservoir to replace any that is destroyed by the UV light. Keeping the actual solution in the pond sanitized is impractical an unnecessary in my experience, all we care is that the plants receive sanitized solution.
Inline filter will treat the water supplied to the plants. The recirc method will treat reservoir solution but not the actual walls, cables, bulkhead fittings, etc... inside your reservoir so you could still potentially have pathogens. You could use both of the methods concurrently but that seems wastful and still doesn't sanitize everything. You mention that prolonged exposure to uv could cause destruction of chelates. Are we talking milliseconds? Minutes? Hours? I would like to use a uv lamp at the specifications you mentioned directly inside my reservoir. I intend to cycle it on and off on whatever schedule would be the proper balance between sanitation and harm to the solution. Assuming safety systems are employed, is this a viable solution?
I don't find it necessary to keep the hydroponic system totally devoid of microorganisms to avoid diseases. Keeping the solution going to the plants sanitized is more than enough, even if the reservoir, pipes, tanks have some level of microorganisms. Recirculating solution through UV is not a good solution, as this destroys the chelates. Heavy metal chelates get destroyed by UV in seconds (5-10 seconds of UV exposure). If you just flow solution through a UV lamp when irrigating, the exposure per irrigation is milliseconds but recirculating will accumulate seconds of exposure within probably less than a single day, depending on the flow rate. Putting a lamp inside the reservoir also doesn't work well, as UV has very little penetration in water (just a couple of centimeters at best). This is why it is important for the UV exposure to happen within a narrow transparent tube. UV in the reservoir will also destroy the chelates quite fast.
Buen dia Daniel, anteriormente tuvimos problemas de pythium en un sistema RDWC de 200lts, con un filtro UVC en linea funcionando unos 10 minutos cada 48hs alcanzaría? funcionaria si el parasito ya esta en la raiz de las plantas? me recomiendan adicionar un ionizador de iones de cobre al filtro UVC, podria eso afectar la solucion nutritiva o haria fluctuar el pH? Gracias Daniel!!!!
En un sistema RDWC es problemático porque habria que circular la solucion constantemente por una lámpara de UV. Solo 10 minutos cada 48 horas no funcionaría. Circular constantement por UV destruiría los quelatos metalicos que tienes en solución. En estos sistemas lo mejor es mantener la oxigenación muy alta y añadir un poco de hipoclorito de ser necesario para tratar las infecciones. Si está además ya en la raiz, el UV no hace nada para tratar la infección, requires de un tratamiento químico.
You can use UV in a flood and drain system. As long as you have your UV filter in line with your pump so that any water going into your plants is sanitized, the UV will help with microbes.
It is a viable solution but in my experience not the best choice. I would rather use either direct sodium hypochlorite or electrolytically generated hypochlorite instead of ClO2.
Thanks for commenting. Very significantly, high turbidity implies that the water has particles suspended that scatter UV light very effectively, heavily reducing its penetration in the medium. Water that is treated by UV light should be optically transparent.
Is it possible that someday you can show us how to make ORP calibration solution and also storage solution? I use chlorine dosing or hydrogen peroxide dosing which keeps the reservoir tank ideally pathogen free. Its popular in the cannabis industry hydroponics systems. I use a lab grade ORP sensor from Atlas Scientific to dose calcium hypochlorite at 4PPM into the rez tank, its the best method for getting healthy roots. You can search aeroponics cloning systems and will find plenty of videos of people using commercial products like "clear rez" which is just distilled water with calcium hypochlorite.
Thanks for commenting! ORP standards are significantly harder to make because of the purity required for the salts used and how hard they are to get. Light's and ZoBell's solutions - the two most common standards for ORP calibration - use ferric and ferrous ammonium sulfates or ferric and ferrous hexacyanoferrates, the first in sulfuric acid and the second in potassium hypochlorite. However, these salts need to be primary standards - which means extremely pure - otherwise the potential deviates significantly because of changes in the Fe2+/Fe3+ ratio (which is what sets the potential). In the case of ORP meters, it is easier and cheaper to buy the standard solutions already prepared.
@@ScienceinHydroponics uv will destroy seaweed fertilizers? I grow carnivorous plants in a hydroponic system and I use only seaweed based fertilizers. I need combat algae and mildew rot.
@@eduardoferreira9882 I wouldn't call it "destroy the fertilizer". The minerals will all still be there, but things like the cytokinins and other such organic molecules present in the kelp will be damaged by the UV light. The presence of these substances will also strongly decrease UV light penetration. So it's not like it won't work as a fertilizer, but you might have different results (not necessarily worse) compared to not using UV light. You will also need to have longer UV exposure times to get the same disinfection.
are you sure about the range you gave on h2o2? according to most sources i've read, 5-10ppm is way to low. I have worked with about 300ppm for months and couldn’t see any effect (weather positiv or negativ) compared to my control group. I added 60ml of a 12% H2O2 solution every 3 days to my 25 ltr to my reservoir (with airstone). After one month, i had biofilm and organic build up anyways, that clogged my nozzels. Plants didn’t seem to be bothered anyways... what do u think? did i miss something?
The issue might be that the H2O2 you add is getting destroyed very quickly. You might want to check the ORP of your water with an ORP meter, see if you are actually getting an increase with your H2O2 additions. For systems that have a lot of things to oxidize much larger additions might be needed to obtain 10 ppm of H2O2 present in solution. Additionally H2O2 is decomposed very efficiently by organisms with catalase, so even large amounts of it can be decomposed very quickly if these organisms are present. This is why oxidants like hypochlorites are usually more effective.
@@ScienceinHydroponics thanks! Finally someone who knows what he is talking about! I also found out that fe3+ can also have a catalytic effect on the decomposition of h2o2. Can u Confirm that? And do u think this effect is big enough to be considered relevant?
@@RadikalBanal Fe3+ will catalytically decompose H2O2, generating much more reactive species (more powerful oxidizers in fact). This however happens mostly with free (non-chelated) Fe3+ in mildly acidic solutions. This is what we call "fenton-mediated-"oxidation. A combination of Fe and peroxide is what we call "Fenton's reagent".
With this UV light, you would need to control the iron in the solution. It will destroy it in a while. I have seen research with this approach and they just added chelated iron every week to compensate for what was destroyed by the light. I would go with something that is biological. Like Bacillus subtilis or something else. For local applications would go with oxygen peroxide.
Thanks for commenting. It is important to realize that Fe is not destroyed by UV light, what will get destroyed is the chelating agent surrounding Fe ions, the Fe itself remains unaffected. Any ill effect from UV light mediated destruction of chelate can be dealt with by just adding excess chelating agent to start with (for example a 20% excess of disodium EDTA). For a system where water only runs once through the UV filter - like a run to waste system - chelate destruction is completely negligible. For a recirculating system, the excess of chelating agent completely fixes the issue if the solution is changed at least once per month. I have never experienced any issues with micronutrient issues in many of the clients I have consulted with who use UV light, even those in recirculating systems, so it is definitely not a reason to shy away from UV. In recirculating systems we just add a bit more chelating agent at the start and things run smoothly. Biologicals are a potential way to manage pathogens in solutions, but they carry their own problems, they are certainly not without significant issues as well (I will do a video on this method of management later on). Bear in mind, having a biologically active system is often not practical in commercial settings. About hydrogen peroxide, it can definitely be used to manage situations that are getting out of hand, but - as I mentioned in the video - some pathogens that produce catalase are extremely resistant to peroxides, so this is not a solution that always works. Effective concentrations of peroxides are often also harmful to plants, particularly smaller ones. Thanks again for commenting and watching my videos!
@@ScienceinHydroponics if I change my nutrient solution once per week should I still consider using a chelate supplement. As it would not be enough holding time to break down the nutrients? Considering your larger clients go for a month
@@michaelgonzales3113 For one week there should be no need to add extra chelate, unless you're permanently irradiating solution. If it is only irradiated on irrigation, then you should be fine for a week.
@@ScienceinHydroponics In a recirculating system for 1 week with irradiation require chelates, considering the entire month would need it will constant irradiation for 1 week recirculating breakdown the nutrients. Thanks for last response!
@@ScienceinHydroponics very helpful information! i guess a week at a time isent enough for pathogens to grow? An RO fresh water holding tanks a sources that should be sterilized repeatedly or as long as the fresh water entering the system irradiated before storage it should be safe prior to mixing nutrients in to the water. or should i only irradiate the water after nutrients are mixed prior to entering the hydroponic system? before being changed out a week later
nice, i use beneficial bacteria in my dwc res, so that type of disinfection is not an option, the "bennies" do the work, but not sure how, seems they have the bigger army :)
hi, thanks for your valuable teaching, I have many questions, I hope you can answer? Is there any specific ORP level for aeroponics or is it treated the same as hydro? Because an aeroponic chamber may be more prone to pathogens, as it has a greater surface area. Say If we have Ph of 5.8, in a full 42L nutrient tank. Could you set a low and high level for ORP that could say turn on a usb Hypochlorous Acid Water Generator at low ORP and turn off at a high ORP to automate any outbreaks? What ORP level should be considered an outbreak? What orp levels are going to hurt roots and how long an exposure? If you feed bennies, will the system be more stable or make ORP settings adjustable? What are ideal temperatures for stable ORP/pathogen control? thanks.
Thanks for commenting! Your questions are complex and would require a lot of time to properly answer. I would be happy to answer them through consulting time, you can book some time on my website (scienceinhydroponics.com/book-now).
An aeroponic chamber is less prone to pathogens because with aeroponics you have the option of running drain to waste so your nutrients are always pristine and free from pathogens. If you recirculate the nutrient all bets are off :)
You should be paid.
Thanks, clear explanation Prof.
Thanks a lot for your comment and kind words!
I've been refreshing the channel to check for updates and finally a new vid! :D
An incredible amount of information, as always. Also, with regards to pathogens, will there be any videos in the future about methods to deal with the different types of pathogen/pests?
I am currently following your blog posts for the 'grape juice'/neem oil/garlic sprays and I was wondering if there will be any updates or instructional videos :)
It feels like the many hobbyist/small-scale farmers around my place just use too many toxic pesticides and I would love to recommend something less harmful.
Thank you!
Thanks for commenting! Great topic suggestion, I'll definitely do a video about that.
How do you add the hypochlorous acid to the reservoirs? I add it first before any nutrients. But don't the nutrients affect the hypochlorous acid content once they are added, should you add another dose of hypochlorous acid after nutrients are added?
I cant seem to get the free chlorine reading on the test strips after the nutrients are added. When I test before the nutrients are added, I get a very clear 2 ppm result.
Thanks for commenting. The nutrients have several things that are oxidized quickly by chlorine, mainly ferrous iron. You should add hypochlorite or hypochlorous acid after you add nutrients and get the free chlorine reading then.
Amazing video. Not sure if I missed it but.. doesn't UV light damage some nutrients like iron chelates? I want to install something a rdwc system.
The UV light will damage organic molecules (like chelates) if the exposure times are too long. For this reason UV light should only be used in line with pumps so that water is sanitized right before irrigation, it should not be permanently shone on the solution nor the solution permanently recirculated through a UV light. The pass through to the UV light should be only done once, when water flows to the plants. In this amount of time, chelate destruction is minimal.
Very nice presentation and information
Glad you liked it
Absolute legend
Great content as always....Love from India.
I have a small clarification, instead of directly installing uv filters in the line of irrigation line, can we install in the pump backflow line? In my case, we use a huge pump of 36m3/hr , whereas pump has a backflow around 5 m3/hr. Can I install Uv across this backflow and help us in controlling pathogens?
Looking forward to your response
Thanks for commenting! This is not ideal because contamination will occur after it goes through the UV filter, in the rest of the irrigation system. A UV system should always be placed as close as possible to the point of release to plants, to ensure maximum effectiveness. However a UV system anywhere will be better than doing nothing.
Great video! I have some questions on making HOCL. When it comes to making your own HOCL is it that you must PH the sodium hypochlorite to 5.8 exactly or can it go below 5.8 and still make the chemical change to HOCL. Also once you have adjusted your solution to 5.8 and made the HOCL can you then raise the PH of your solution without affecting the HOCL? Or will raising your PH from 5.8 negatively affect the HOCL in the solution.
When making your own HOCl, be careful with concentration. One thing is generating s very small amount of HOCl by adding a very small amount of bleach to a nutrient solution, a very different thing is to try to lower the pH of a concentrated bleach solution (dangerous as this generates chlorine gas). Never create HOCl solutions with a concentration higher than around 250 ppm. Any pH below around 7 will already imply all the hypochlorite converts to hypochlorous acid, anything in the 5.5-7 range is acceptable as far as HOCl goes.
I just made the HOCl solution based on your protocol. The master grower at the facility said that the athena cleanse smells very strong and their pH is very low (4) so he doesn’t believe my product is right 😅.
Very informative 👍🏻
Glad it was helpful!
amazing content!
Fantastic video, as im sure your aware early hydroponicum researchers delivered solutions heated, either sanitation was an unforeseen benefit or intended purpose and don't recall what their reasoning was, just know it became discontinued practice. Was this due to addition of 2ppm chlorine?
Thanks for commenting! I don't recall early hydroponic researchers heating up solutions, so I'll need to discuss with some of my colleagues to verify this for you and answer the question.
Thank you I've been going through my research archives lately so perhaps will stumble across it in an update.. I do know there was bed heating done in colder climate pre WW2 as well cooling in hot such a middle east and India by U.S military and OIL CO outposts 30's -40's but this was related to other factors if I recall and think it's was earlier than that.
My peak of interest never quite resolved was resulted from early patent searching and devices and stumbled across the solution heating and delivery mechanical patents was where it originated. If memory serves and it's a little slower now lol it was said to be scalding temp then cooled before addition. What I do know is it wasn't for distillation of which they did do to such a huge extent it was mind boggling.
Another theory coming to mind they believed it somehow thought it kept a precipitation of FE from occuring l but can't recall what I read that leads to that thought that pops up now lol.
If you come up short I'll update this for the historic reference if nothing else as now I'm preoccupied to figure it out.
I'm a bit of a hydo history buff, it's so facinating as well the little known politics behind the scenes in those days that need to take into account reading the publications.. eg Hoagland speaking against all the sensationalism, downplaying the commercial and hobby aspects but here we are today what he spoke against is now fact and his formula the basis.
Little known was the politics of Gericke vs the University Hoagland and Knopp at that writing.
Thank you.
What would you recommend for a large DWC pond (cement pond) where the water is rarely replaced?
In my experience, it is very difficult to add hypochorite because it reacts rapidly with plant roots making it seem like the concentration is not high (when testing with strips or titration), meanwhile I’ve almost killed an entire crop this way trying to reach a few ppm. Also, I worry about chloride buildup, or unwanted sodium or calcium.
When I spoke to Dramm they recommend ozone systems saying that the oxygen biproduct makes you better off than you stated, and while I heard of chelate degradation and precipitation, these issues are less costly than pathogens.
In my case it does not help me much to know my input water is clean, because the pond is constantly recirculating for a very long time. I have experienced root rot sometimes and need a way to knock down pathogens and something constant to make sure they do not return. In my case it is not feasible to sanitize a pond for very long.
Thanks for commenting. In your case, putting an inline UV system right after your pump would be the most effective solution to keep your solution sanitized. This way we really don't care about pathogens in the pond, but just ensure that anything that is fed to plants is sanitized. Adding a 50% excess of chelating agent would also help maintain a chelate reservoir to replace any that is destroyed by the UV light. Keeping the actual solution in the pond sanitized is impractical an unnecessary in my experience, all we care is that the plants receive sanitized solution.
You can also prevent root rot with adding oxygen with an air pump.
Inline filter will treat the water supplied to the plants. The recirc method will treat reservoir solution but not the actual walls, cables, bulkhead fittings, etc... inside your reservoir so you could still potentially have pathogens. You could use both of the methods concurrently but that seems wastful and still doesn't sanitize everything.
You mention that prolonged exposure to uv could cause destruction of chelates. Are we talking milliseconds? Minutes? Hours?
I would like to use a uv lamp at the specifications you mentioned directly inside my reservoir. I intend to cycle it on and off on whatever schedule would be the proper balance between sanitation and harm to the solution.
Assuming safety systems are employed, is this a viable solution?
I don't find it necessary to keep the hydroponic system totally devoid of microorganisms to avoid diseases. Keeping the solution going to the plants sanitized is more than enough, even if the reservoir, pipes, tanks have some level of microorganisms. Recirculating solution through UV is not a good solution, as this destroys the chelates. Heavy metal chelates get destroyed by UV in seconds (5-10 seconds of UV exposure). If you just flow solution through a UV lamp when irrigating, the exposure per irrigation is milliseconds but recirculating will accumulate seconds of exposure within probably less than a single day, depending on the flow rate.
Putting a lamp inside the reservoir also doesn't work well, as UV has very little penetration in water (just a couple of centimeters at best). This is why it is important for the UV exposure to happen within a narrow transparent tube. UV in the reservoir will also destroy the chelates quite fast.
Buen dia Daniel, anteriormente tuvimos problemas de pythium en un sistema RDWC de 200lts, con un filtro UVC en linea funcionando unos 10 minutos cada 48hs alcanzaría? funcionaria si el parasito ya esta en la raiz de las plantas? me recomiendan adicionar un ionizador de iones de cobre al filtro UVC, podria eso afectar la solucion nutritiva o haria fluctuar el pH? Gracias Daniel!!!!
En un sistema RDWC es problemático porque habria que circular la solucion constantemente por una lámpara de UV. Solo 10 minutos cada 48 horas no funcionaría. Circular constantement por UV destruiría los quelatos metalicos que tienes en solución. En estos sistemas lo mejor es mantener la oxigenación muy alta y añadir un poco de hipoclorito de ser necesario para tratar las infecciones.
Si está además ya en la raiz, el UV no hace nada para tratar la infección, requires de un tratamiento químico.
@@ScienceinHydroponics muchas gracias Daniel!
Im coming back to this video, could you go into more information about iodine?
I will! Thanks for commenting!
@@ScienceinHydroponics What form of iodine is recommended?
@@Runboy7426 Normally you would use potassium iodide for disinfection purposes. Between 0.3-0.6ppm of elemental iodine from KI.
it will be effective in a flood and drain system? the pump run 10 minutes and wait 50 mins for drain.
You can use UV in a flood and drain system. As long as you have your UV filter in line with your pump so that any water going into your plants is sanitized, the UV will help with microbes.
What are your thoughts on chlorine dioxide in RDWC?
It is a viable solution but in my experience not the best choice. I would rather use either direct sodium hypochlorite or electrolytically generated hypochlorite instead of ClO2.
How does turbidity affect the efficiency of the UV filter? Thanks
Thanks for commenting. Very significantly, high turbidity implies that the water has particles suspended that scatter UV light very effectively, heavily reducing its penetration in the medium. Water that is treated by UV light should be optically transparent.
Do you have any experience using collaidal silver as resorvoir sanitant?
Thanks for commenting. No, I don't have any experience using silver for this purpose.
Colloidal silver would absolutely work without harming the good bugs or the plant roots.
Is it possible that someday you can show us how to make ORP calibration solution and also storage solution? I use chlorine dosing or hydrogen peroxide dosing which keeps the reservoir tank ideally pathogen free. Its popular in the cannabis industry hydroponics systems. I use a lab grade ORP sensor from Atlas Scientific to dose calcium hypochlorite at 4PPM into the rez tank, its the best method for getting healthy roots. You can search aeroponics cloning systems and will find plenty of videos of people using commercial products like "clear rez" which is just distilled water with calcium hypochlorite.
Thanks for commenting! ORP standards are significantly harder to make because of the purity required for the salts used and how hard they are to get. Light's and ZoBell's solutions - the two most common standards for ORP calibration - use ferric and ferrous ammonium sulfates or ferric and ferrous hexacyanoferrates, the first in sulfuric acid and the second in potassium hypochlorite. However, these salts need to be primary standards - which means extremely pure - otherwise the potential deviates significantly because of changes in the Fe2+/Fe3+ ratio (which is what sets the potential).
In the case of ORP meters, it is easier and cheaper to buy the standard solutions already prepared.
Sir, if i use uv light can i add some additive like seaweed extract?
You would need to add them after the water has passed through the UV light, otherwise the UV will unfavorably interact with those substances.
Ok thanks
@@ScienceinHydroponics uv will destroy seaweed fertilizers? I grow carnivorous plants in a hydroponic system and I use only seaweed based fertilizers. I need combat algae and mildew rot.
@@eduardoferreira9882 I wouldn't call it "destroy the fertilizer". The minerals will all still be there, but things like the cytokinins and other such organic molecules present in the kelp will be damaged by the UV light. The presence of these substances will also strongly decrease UV light penetration.
So it's not like it won't work as a fertilizer, but you might have different results (not necessarily worse) compared to not using UV light. You will also need to have longer UV exposure times to get the same disinfection.
@@ScienceinHydroponics thanks 🤩
are you sure about the range you gave on h2o2?
according to most sources i've read, 5-10ppm is way to low. I have worked with about 300ppm for months and couldn’t see any effect (weather positiv or negativ) compared to my control group.
I added 60ml of a 12% H2O2 solution every 3 days to my 25 ltr to my reservoir (with airstone). After one month, i had biofilm and organic build up anyways, that clogged my nozzels. Plants didn’t seem to be bothered anyways...
what do u think? did i miss something?
The issue might be that the H2O2 you add is getting destroyed very quickly. You might want to check the ORP of your water with an ORP meter, see if you are actually getting an increase with your H2O2 additions. For systems that have a lot of things to oxidize much larger additions might be needed to obtain 10 ppm of H2O2 present in solution.
Additionally H2O2 is decomposed very efficiently by organisms with catalase, so even large amounts of it can be decomposed very quickly if these organisms are present. This is why oxidants like hypochlorites are usually more effective.
@@ScienceinHydroponics thanks! Finally someone who knows what he is talking about!
I also found out that fe3+ can also have a catalytic effect on the decomposition of h2o2. Can u Confirm that? And do u think this effect is big enough to be considered relevant?
@@RadikalBanal Fe3+ will catalytically decompose H2O2, generating much more reactive species (more powerful oxidizers in fact). This however happens mostly with free (non-chelated) Fe3+ in mildly acidic solutions. This is what we call "fenton-mediated-"oxidation. A combination of Fe and peroxide is what we call "Fenton's reagent".
@@ScienceinHydroponics thanks! so u would consider this effect negligible?
@@RadikalBanal If your Fe is chelated with EDTA, DTPA or EDDHA then yes. If you're using Fe from Fe sulfate it could be an important effect.
With this UV light, you would need to control the iron in the solution. It will destroy it in a while. I have seen research with this approach and they just added chelated iron every week to compensate for what was destroyed by the light. I would go with something that is biological. Like Bacillus subtilis or something else. For local applications would go with oxygen peroxide.
Thanks for commenting.
It is important to realize that Fe is not destroyed by UV light, what will get destroyed is the chelating agent surrounding Fe ions, the Fe itself remains unaffected. Any ill effect from UV light mediated destruction of chelate can be dealt with by just adding excess chelating agent to start with (for example a 20% excess of disodium EDTA).
For a system where water only runs once through the UV filter - like a run to waste system - chelate destruction is completely negligible. For a recirculating system, the excess of chelating agent completely fixes the issue if the solution is changed at least once per month.
I have never experienced any issues with micronutrient issues in many of the clients I have consulted with who use UV light, even those in recirculating systems, so it is definitely not a reason to shy away from UV. In recirculating systems we just add a bit more chelating agent at the start and things run smoothly.
Biologicals are a potential way to manage pathogens in solutions, but they carry their own problems, they are certainly not without significant issues as well (I will do a video on this method of management later on). Bear in mind, having a biologically active system is often not practical in commercial settings.
About hydrogen peroxide, it can definitely be used to manage situations that are getting out of hand, but - as I mentioned in the video - some pathogens that produce catalase are extremely resistant to peroxides, so this is not a solution that always works. Effective concentrations of peroxides are often also harmful to plants, particularly smaller ones.
Thanks again for commenting and watching my videos!
@@ScienceinHydroponics if I change my nutrient solution once per week should I still consider using a chelate supplement. As it would not be enough holding time to break down the nutrients? Considering your larger clients go for a month
@@michaelgonzales3113 For one week there should be no need to add extra chelate, unless you're permanently irradiating solution. If it is only irradiated on irrigation, then you should be fine for a week.
@@ScienceinHydroponics In a recirculating system for 1 week with irradiation require chelates, considering the entire month would need it will constant irradiation for 1 week recirculating breakdown the nutrients. Thanks for last response!
@@ScienceinHydroponics very helpful information! i guess a week at a time isent enough for pathogens to grow? An RO fresh water holding tanks a sources that should be sterilized repeatedly or as long as the fresh water entering the system irradiated before storage it should be safe prior to mixing nutrients in to the water. or should i only irradiate the water after nutrients are mixed prior to entering the hydroponic system? before being changed out a week later
How can ppm of H2O2 and iodine measured in nutrient solution ?
Thanks for commenting! There are testing strips available to measure both chemicals at the required range.
What about inoculation of microbes that may attack these pathogens?
Thanks for commenting! This is not disinfection but another type of solution to the problem. I will discuss it in a future video.
nice, i use beneficial bacteria in my dwc res, so that type of disinfection is not an option, the "bennies" do the work, but not sure how, seems they have the bigger army :)
@@crackbabies_dwc What type of bacteria do you use? Is there a product name that you can share?
miracle powder, my water temps are 75f+, no rot :)
well seems links are a no go, company is aquascape
hi, thanks for your valuable teaching, I have many questions, I hope you can answer? Is there any specific ORP level for aeroponics or is it treated the same as hydro? Because an aeroponic chamber may be more prone to pathogens, as it has a greater surface area. Say If we have Ph of 5.8, in a full 42L nutrient tank. Could you set a low and high level for ORP that could say turn on a usb Hypochlorous Acid Water Generator at low ORP and turn off at a high ORP to automate any outbreaks? What ORP level should be considered an outbreak? What orp levels are going to hurt roots and how long an exposure? If you feed bennies, will the system be more stable or make ORP settings adjustable? What are ideal temperatures for stable ORP/pathogen control? thanks.
Thanks for commenting! Your questions are complex and would require a lot of time to properly answer. I would be happy to answer them through consulting time, you can book some time on my website (scienceinhydroponics.com/book-now).
An aeroponic chamber is less prone to pathogens because with aeroponics you have the option of running drain to waste so your nutrients are always pristine and free from pathogens. If you recirculate the nutrient all bets are off :)