Root Rot and High Res Temps

Ambient temps where I live have been rising to 85f, which keeps my grow tent around 90f. Yesterday I saw root rot for the first time. I thought I cleaned it up and the plant started looking healthier, but when I came home last night I could smell it around my tent and when the lights came back on this morning I checked and they're covered in brown slime again. I'm using DWC with the (organic) FF hydro trio. When I refilled the bucket yesterday I used all 3 nutes (the NPK ratio was closer to lucas' formula than either nute alone) and I added aquashield and liquid humus. I only have 2 dying plants (first grow...) in a small tent, so I'm thinking about throwing them away and starting fresh with a new system and new plants.I'm thinking about doing an ebb and flow system in the buckets I have now. That would let me cool the water easier, and seems less prone to bacteria growth. I'm also planning on switching to non-organic nutrients, probably just maxiblom because it's the cheapest way to get lucas' ratio. I don't have any H2O2, but I'll probably buy some of that too. How hard would it be to keep a ebb and flow system like this sterile, if the temps stay around 85-90f?

I use frozen water bottles works fine.Gonna have to get the tents temp down and what are you gonna do when summer is here....If its tht hot now only gonna get hotter.
Beech

Frozen water bottles are a must if no cooling is available. Try a good beneficial like great white or pondzyme.

Temps are your secondary problem. Get rid of the organic nutes and you'll go a long way to fixing things.

I would not recommend switching growing method, fix your issues (temps) and finish the grow.

regards,