Green Mopho
Grower of Many Things
In 2022 I got to run a very expensive and large aeroponic facility. I hadn't done aero or DWC in over a decade, but not much changed as far as your options for root conditioning. Basically, you can use biologicals, like bacillus, trichoderma, and mycorrhizae, but they have mostly insoluble carrier powders and will also leave other types of biofilm and sediments in your system. The other option is to run sterile, where your options are basically chlorine compounds or H2O2.
UC roots is hypochlorous acid, and is insanely priced for the concentration you are getting. Adding H2O2 to chlorinated water will oxidize the water and create chlorine gas and make both the chlorine and peroxide dissipate faster. Don't use both, use one or the other. Chlorine compounds will stay around a lot longer than peroxide. Peroxide will only linger around 12 hours, and can also cause major oxidative damage at too high of a rate. Its only good if you have an active root infection and want to work immediately to fight it.
I found that beneficial biology to be the most effective in rooting clones, and then switching to a sterile system. Don't bother with ORP meters and readings. Buy some free chlorine test strips and keep your free chlorine around 1-3 ppm all the time. Calcium hypochlorite (pool shock treatment) is a good option for constant use, say every 2-3 days, as your plants will also use the calcium up. You can also use sodium hypochlorite (bleach) when in a bind, but it does add sodium to the system, so I wouldn't regularly add it, but you could use it as a dirt cheap cleaner in between runs.
As far as the TDS of your water coming in, 280 ppm is a problem, and its not the chlorine or chloramine content thats the worry. If you had a buffered media like soil or coco or peat, it would be way less of an issue as the media itself will buffer some of that. But in DWC, your roots are swimming in that tap water, and probably a good bit of sodium, magnesium, carbonate, bicarbonate, etc., plus potentially toxic amounts of copper and possibly some lead, arsenic, causing all sorts of issues. I would invest in an RO system, even a very small one. Small RO systems are very slow, so you could put it on a float valve on the whole system to replenish the water that your plants are transpiring. A healthy aero or DWC system generally means the plants are drinking more than they are eating, and keeping your nutrient TDS/EC consistent means constantly adding back more water. Plus, the treatment they are putting in is at also to keep the old plumbing and pipes from leaching more metal that they need to. The ideal levels are added at the treatment plant, miles from where you are using it, so there is still plenty of plumbing between you and the treatment plant for the water to get re-contaminated. Have you seen the insides of some of those 30+ year old city pipes?
As far as biological contaminants coming in your tap water, this is very possible. Most municipal water is treated with the minimum threshold levels of chlorine, etc. to kill biological contaminants. They are trying to get rid of E. Coli and other harmful microbes to humans, but the last thing they are thinking about is a recirculating bare root plant growing system. I have seen plenty of algae and cyanobacteria come through municipal water, and even make it through RO membranes to the other side. Adding a UV filter after your RO is ideal, but will only stop some of the potential microbial contamination coming in. You still need to maintain ideal free chlorine levels to keep everything back.
At the end of the day, growing like this is such a hassle and requires all this extra steps, cleaning, chemicals, that I found it not worth it. Just grow in coco!
UC roots is hypochlorous acid, and is insanely priced for the concentration you are getting. Adding H2O2 to chlorinated water will oxidize the water and create chlorine gas and make both the chlorine and peroxide dissipate faster. Don't use both, use one or the other. Chlorine compounds will stay around a lot longer than peroxide. Peroxide will only linger around 12 hours, and can also cause major oxidative damage at too high of a rate. Its only good if you have an active root infection and want to work immediately to fight it.
I found that beneficial biology to be the most effective in rooting clones, and then switching to a sterile system. Don't bother with ORP meters and readings. Buy some free chlorine test strips and keep your free chlorine around 1-3 ppm all the time. Calcium hypochlorite (pool shock treatment) is a good option for constant use, say every 2-3 days, as your plants will also use the calcium up. You can also use sodium hypochlorite (bleach) when in a bind, but it does add sodium to the system, so I wouldn't regularly add it, but you could use it as a dirt cheap cleaner in between runs.
As far as the TDS of your water coming in, 280 ppm is a problem, and its not the chlorine or chloramine content thats the worry. If you had a buffered media like soil or coco or peat, it would be way less of an issue as the media itself will buffer some of that. But in DWC, your roots are swimming in that tap water, and probably a good bit of sodium, magnesium, carbonate, bicarbonate, etc., plus potentially toxic amounts of copper and possibly some lead, arsenic, causing all sorts of issues. I would invest in an RO system, even a very small one. Small RO systems are very slow, so you could put it on a float valve on the whole system to replenish the water that your plants are transpiring. A healthy aero or DWC system generally means the plants are drinking more than they are eating, and keeping your nutrient TDS/EC consistent means constantly adding back more water. Plus, the treatment they are putting in is at also to keep the old plumbing and pipes from leaching more metal that they need to. The ideal levels are added at the treatment plant, miles from where you are using it, so there is still plenty of plumbing between you and the treatment plant for the water to get re-contaminated. Have you seen the insides of some of those 30+ year old city pipes?
As far as biological contaminants coming in your tap water, this is very possible. Most municipal water is treated with the minimum threshold levels of chlorine, etc. to kill biological contaminants. They are trying to get rid of E. Coli and other harmful microbes to humans, but the last thing they are thinking about is a recirculating bare root plant growing system. I have seen plenty of algae and cyanobacteria come through municipal water, and even make it through RO membranes to the other side. Adding a UV filter after your RO is ideal, but will only stop some of the potential microbial contamination coming in. You still need to maintain ideal free chlorine levels to keep everything back.
At the end of the day, growing like this is such a hassle and requires all this extra steps, cleaning, chemicals, that I found it not worth it. Just grow in coco!
