I'm running a chiller everything at 18 degrees c ...clean between crops with bleach then sprayed with isopropyl alcohol. changed water every 10 days was using anti pythium additive every time water went in res...the only thing I've been thinking is whether as its an aero system (amazon) the roots hanging in the air chamber, even though being sprayed with nice cool water.. the air is getting to warm.... as with all hydro stuff its all black plastic so gets warm on the outside. the top is covered in reflective foil which also makes it light tight.,,, thought having my chiller would have sorted most of these issues.. hence why I've bought 6 autopots and loads of seeds.:banghead: