After starting treatment with H2O2 I did some research on the forum and found your bleach method for Pyth.I feel This method would be better than H2O2 . You gave me some advice on my next system build that I really appreciate. I was wondering in my current Aero Flo 60 would you treat the Pyth problem with bleach in deep water or continue to run empty in the runners and on the timer?I know its a bad system prone to these type of problems but I have no choice but to grow in this until I complete the next system I think I will be going in 10in wide 20 in deep runners on the next one.Thanx for all your assistance. Forgot I use water max By Bobs Brew don't know if this would react with bleach think its at bobsbrew.net,Thanx again