copied and pasted...hope this helps..Im a dirt farmer..
COMBATING EXISTING ROOT ROT:
If you have some grungy roots on established plants, then I'd go with 1/2 cup of hydrogen peroxide (3 - 4% strength) per gallon in a full reservoir. Plan on changing the res every 4 or 5 days until the problem is under control.
The peroxide will kill the bacteria, and make a mess of your reservoir if the problem is progressed, so the increased res changes are important to keep things clean. There are no guarantee's when it comes to rootrot problems that are very progressed.
You can repeat this process until you see some new white roots developing, then keep up the 1/2 cup per gallon for the rest of the life of these particular plants.
During this intense method, I'd drop your nutrients down to half of what you were using before until the plants show healthy new growth.
You should also discontinue the use of any 'live' innoculants (products that are alive like Subculture, or any mycchorizal fungus) while you're taking this approach, as the peroxide will just kill them off.
The peroxide will kill the bad bacteria, but if the problem is too far gone, then the plants are already stressed, and the peroxide may further stress them, but we have had very positive results with this approach where nothing else will work though.
We've got several 'zyme' type products that are designed to be used with the peroxide to 'eat' up the dead root tissue. They work incredibly well, but are pretty expensive products. You don't absolutely have to use the zyme products to have the peroxide work, but it really helps keep the roots healthy and clean if you've got a severe problem. Some of these products are: Hygrozyme, Power Zyme, and Prozyme.
The 1/2 cup recommendation is half of what some of our customers run. You may need to add more to get rid of a bad problem, up to 1 cup per gallon. All of these recommendations are based on 'off the shelf' hydrogen peroxide, which is 3 - 4% strength.
ROOT ROT PREVENTION:
If you're just starting out with a new or sterilized reservoir, and new plants (no rot), then I'd start a program of one tablespoon hydrogen peroxide (3 - 4% strength) per gallon, and re-add the same every 5 days.
The peroxide dissipates, and is basically gone after 4 or 5 days, so re-adding it is important.
Change the reservoir as you normally would.
As an added bonus, the peroxide also helps oxygenate the nutrient solution and your plants will love it.
take care and be safe
