Pythium Saga In Rdwc

I wanted to put some information out there regarding my ongoing war against root rot in my RDWC system. My issues are somewhat different from the majority of information I have found online, and by spending months researching the problem I have come to some conclusions that differ from the majority.
 
My first grow I used GH power growers that I modified to recirculate. I had amazing success. I was using RO water and my source was municipal water... Treated. Sure I was removing the chlorine using RO, but the water I was feeding my RO filter was already of good quality and free of most pathogens.
 
Then I moved to another location which had a well and starting using RDWC. Being relatively new to hydroponics water quality was something I considered, and used RO, but I knew little about water born pathogens and removing them. I would like to get my water tested, but I have come to conclusion pythium and it's relatives are in my water supply. I have tried everything from H202, bennies, bleach, and now fungicides.
 
Assuming pythium or another pathogen is in my water supply most of the steps I was taking to correct the problem were negated by the pathogen being reintroduced every time I flushed the system. This is counter intuitive to my knowledge of hydroponics which suggested starting with fresh nutes will correct many issues.
 
My new course of action which I want share with the community is to sterilize my RO water. At the moment after fighting this shit for over a year I can't afford a UV sterilizer for my filter, so I am using a low dose of bleach. 1ml to 10 gallons. I believe this will sterilize the incoming water. My plan is to dose my nutrient solution with the bleach when I mix a fresh batch.
 
I am also experimenting with fungicides. Banrot, Subdue Max, and Alliete are the three that seem most effective in my research. I have started using banrot as a soak for my rock wool cubes. It seems to be working. My understanding is that you need to rotate the fungicides. The fungicide is only being used in veg, not in flower.
 
My idea is to use a rotating preventative treatment of fungicides early on to prevent early infection and help the plants fight the pathogens that are already in the system. I can't just scrap my whole garden at this point and start over.
 
The bleach will keep the pathogen from being reintroduced. Eventually, after the bleach and fungicide treatment I believe I will only need to run a dead rez in veg. Starting with good sterile water and healthy plants I believe I will be able to go back to using EWC Tea in flower in my DWC. However, I believe in my circumstance EWC is not enough to keep the pathogen at bay because it is in high level in my well water. I believe it starts in my trays and explodes in my DWC. I also believe since the crowns are not in the solution once the plants are infected no amount of tea will help the crowns.
 
When the garden comes back to normal I am also interested in testing a low dose of systemic fungicide directly in my rez as a preventative measure in veg.
 
Most of the time people seem to blame pythium on cultural practices and do think my rock wool has been subject to excessive moisture. But my feeding schedule and system has remained constant and I have seen great results from it.
 
Lastly in my trays I started noticing algae on the rock wool and then right where the drippers lands on the cubes a brown rot that spreads. Instead of staying on the surface it get's into the rock wool and eventually rots the stem from the core. Algae has never caused problems for me in the past.
 
When I transplant my roots look beautiful in the DWC but the cores of the rock wool cubes are rotten and the plants literally fall over. When they die you can pull them out of the cubes easily. The DWC is running correctly, but cannot compensate for an infection above the water line. Moving the water line to the cubes only makes things worse because it makes the cubes too wet.
 
In conclusion I believe my pythium problem is not the result of bad DWC practices and rather the result of contaminated water. The disease starts in my propagation tray and explodes when it hits my DWC system. I believe sterilizing my RO water to be the key to preventing it and to deal with it in already infected plants in my tray I am using fungicidal soaks. The soaks may not be as effective as it is designed for soil, but I am hoping to develop an appropriated dosage I can feed the plants in early veg directly in the nutrient.
 
Normally I don't like sharing anything about my garden, but this has cost me too much time, money, and aggravation for me not to contribute to the community. Especially considering most of the information I have found regarding the disease concerns root health in DWC and not crown rot. My roots are awesome under water, nasty at the crown.
 
Questions, comments, let's develop this thread so we can help people get rid of this shit. I will update with my results.

 

Status update:
 
Banrot has destroyed the infection. All plants are in full recovery. I ended up adding it to my reservoir, about 5 heaping tablespoons in about 140 gallons and letting it circulate in the drip tray for a week. Roots that were tan and brown are dead and new huge white root shoots are starting to take over the rock wool in place of the dead roots. Even the worst plants are showing new white roots and starting to recover. The plants that were not infected are crushing it, and the plants with mild infections are back to normal growth.
 
After running the Banrot in the reservoir with GH 3 part in veg, Cal-Mag and Merit at 400 ppm the plants in the tray are showing good growth. The only thing I noticed is the new growth continued but got a little abnormal. The new growth looked a little oversaturated and had an abnormal sheen. The existing growth was not looking good and showing signs of infection from the pathogen when treatment started. I will lower the dosage of the fungicide until a find a mix that prevents infection than shows now abnormal growth.
 
I changed the reservoir and remixed without any pesticides. I am going to let the plants continue growing and retreat in 4-7 days. It is important to note that I am not treating flowering plants. I do not use any pesticides once the plants hit day one of flower. I believe preventative systemic fungicides and pesticides incorporated into the propagation cycle may be the key to hassle free gardening.  
 
In the case of my battle with pythium nothing was working but this seems to be a silver bullet combined with monitoring and letting the rock wool dry out a little. I also noticed brown patches in the field outside my place. I suspect pythium is in the fields outside my building and probably also in the well water. The long term approach to mitigation will be using UV sterilization for my RO, running a dead reservoir in the veg, and using fungicides.
 
Because pythium eventually took over my system, even my tried and true veg tray, I really think in some cases fungicides are appropriate. If it is a persistent problem and you have had success with your technique before consider your water source and environment before you give up on hydro. In my case changing locations helped me hone in on the water source being the likely culprit with the alternate method of introduction being airborne or spread by insects from the infected fields outside my building.
 
My goal is to correct the problem in veg and pretreat the plants before they go into flower. Then when they go into flower going back to my proven bennies in my DWC for flower. Since the pesticides are systemic I think treating them in the tray before the transition should prevent any further issue without risking the chemicals ending up the buds.
 

 

Status Update:
 
My aero cloner started with 100% success rate when I got it and gradually dropped to 35% over the years using it. This batch I added a Teaspoon of the Banrot in the cloner and got 100% success again with nice roots in 2 weeks. The new growth is affected a little by the banrot, but the roots are pearly white. The clones have been in rockwool cubes for 1 week now and are already showing roots through the bottom of the 4x4 cubes. So I am certain now that some species of water born mold is to blame for my root rot issues.
 
Concerning the RDWC. Read this study: https://www.apsnet.org/publications/phytopathology/backissues/Documents/1988Abstracts/Phyto78_1409.htm
 
Also good read:
http://www.apsnet.org/edcenter/intropp/lessons/fungi/Oomycetes/Pages/PythiumBlight.aspx
 
What it says is that even high doses of commonly accepted fungicides do not killed the thick walled oospores. It also says the only way to kill the thick walled oospores which are a survival mechanism of the pathogen is heat of 70C for 30 min. When the mold dies it leaves behind thick walled oospores which are resilient and can withstand adverse conditions.
 
After rereading this I thought I would idiot proof your train of thinking and mention heat treatments are for cleaning the system and not curing the plants. Once the plants have it you must battle it with your desired method. Fungicides, H202, Chlorination, Bennies, or Tea.. Bennies do seem to work the best at helping to heal the plants in my opinion, however they tend to make my PH drift and will not just cure a plant. In my experience there really has been no cure once I got to the point where it had infested my system. Prior to infestation I could save plants, but at this point I think the spores are all over my air rings and net pots.
 
Also bleach and h202 do not kill these spores. Whether this is true or not I do not know, but I have found a study suggesting even if direct contact with an oxidizing agent does kill the thick walled oospores, oxidizers are not good at sterilizing porous surfaces. So my theory on this is that once you are infected and infested the only way to clean air rings, pumps, hoses, drippers, lids and net pots is with heat treatment. My research also suggests that the approved cleaning methods we are using as a whole community are flawed and that chemical sterilization of our hydroponics equipment simply isn't possible or not cost effective. Now I am not a microbiologist but anecdotal evidence from Chlorox suggests that bleach is not effective at cleaning porous surfaces. Air Rings?... hello...! And plastic is somewhat porous as well, as is rubber.
 
So what if this stuff is always present all the time in trace amounts everywhere. We 'culture' our plants and this just happens to be a great environment for water born molds. These mold take time to build up and do no harm when the system is new. Our cleaning methods are not 100% effective and over time we start to build the spores up. After a certain amount of time in the system the spores take over and plants start dying. Our goal should be a sterile environment after every cleaning and we are not achieving this.
 
In my case I am using a relatively shallow well. I never had a problem using city water. It took years of growing in one location for it to accumulate but now that it has I have lost 3 consecutive crops due to the infection and using identical cultural practices that had brought me killer crops. The idea of a flawed method of cleaning explains how the problem was location specific and built up over time. It also explains why the infection has always been at peak in summer. Having only grown in the location for 2.5 years it took that long to see a pattern of infection that go worse in the summer and better in the winter and this makes sense as well. My source water's contamination is at its peak in the summer when the ground is not frozen.
 
This is actually a breakthrough for me because it means there is a way to sterilize your equipment, but the way we have been trying to do this is all wrong, and it makes sense when you think about it. Most industries that need sterilization rely on heat to accomplish this. Think about baby bottles and canning. They don't use h202 or bleach, they use heat. Greenhouses don't treat soil using h202 they use heat treatments.
 
My plan of action also includes UV sterilization of my RO water to eliminate the source, but I do not believe the levels of the pathogen are high enough in the well water to cause real damage in one or two crop rotations having had great success in the past using it. I would only see root rot at the very end of the cycle and then it didn't matter because the plants we ripe and killing it.
 
Once the infestation is present the cleaning we are doing is only killing the pythium in one of it's life cycles. Chlorinations and oxidization are good at preventing the infection from spreading, but it is my belief that levels high enough to kill the mold also hurt the plants. So these treatments are effective, as preventatives. Imagine these hard shelled oospores stuck to every porous surface of your hydro equipment just waiting to come back to life. This is why heavy cleaning has not solved the problem for me. However chlorination and oxidation with the goal of running a dead res does help and kill the mold in one of it's life cycles, probably the zoospore stage. All of dead rez attempts are probably killing the zoospores but not the sporangia or mycellium. It is my believe to kill the sporangia would also take cleaning agents that are also harsh enough to kill the plant. The plants themselves can fight off an infection and killing it in its reproduction life cycle would sometimes allow a plant to recover and outgrow the infection.
 

 
Banrot does work but it will not save plants once they are heavily infected. It is my belief once a plant is starting to yellow and die there really isn't anything that will bring them back past a certain point. The problem with the banrot is the new growth is effected and the plants just don't like it at levels that can really kill the infection dead. So prevention is the best remedy, but to do that you have to successfully clean your system. People say to through out your air rings, but no one I have found online has ever mentioned using heat to clean. Banrot is a good preventative measure before an infection if you have been dealing with one. I find 1-2 tablespoons in 150 gallons nutrient res adequate to prevent and control infection before it starts. I only use this product in early veg not in flower.
 
Hot water is clean, leaves no residue, and is 100% effective at sterilization. For the moment I am going to dishwash all my equipment that will fit at high heat. Eventually I am going to buy a water boiler so I can fill the entire system with 80C water and let it sit in there overnight and cool gradually. I will monitor the temp to make it sure it stays above 70C for at least an hour. It should be better and probably cheaper than bleach or H202 and leave no residue. I should also mention I realize sterilization will not be achieve completely at 70C, but given the study it should be hot enough to kill the specific spore we are targeting, while not damaging the equipment. I don't think the heat will hurt the uniseals, but that is the beauty of having multiple systems.
 
For sterilization of hydroton baking seems best because it can achieve a higher temperature which makes it possible to actually sterilize hydroton.
 
And come on guys lets get updated and stop calling this stuff a fungus, it is a mold. Once you start seeing it as a mold it will change the way you think about it and how you treat for it.

 

Sorry, to reply to Ttystikk:
 
Unfortunately I do not have water chiller and realize the importance of water temperature at controlling the pathogen. However, my rest temps stay about 72 all the time and having had great success in the past without them I do not believe them to be 100% necessary. Having said that they are first on my list of upgrades, but do upgrade I must have a successful crop. 72 is a still acceptable in DWC although on the high end. I want a water chiller to increase my DO levels and gain control of that variable and also to help with the pathogen. But if my theory is right the real key will be sterilizing my system versus disinfecting it.