MY ROOTS ARE ROTTING! What can I do?

This is my first grow.
Today I noticed my roots are starting to turn brown. Ive read that you can treat this using hydrogen peroxide. All I have is the standard 3% until tomorrow when the hydro store opens. Is there something I can do with the 3% until then? I think my res water is too warm.tomorrow Im getting a better air pump to try to cool it down. Is there anything else I can do about the water temp?
Im running a 2ftx 3ft x6 ft space with a 400w air cooled light.
20gal res
air temp75
ppm 600
ph6-6.5
Is there anyone who can help? I dont know how much to add or anything.
Any help is appreiciated

Yes I have heard that also but pics would help.
Root rot is a hard thing to treat. You might be better off disinfecting the area and starting over.

no h2o2! it kills beneficials....

what's the res temp? any light leaks? find the problem, that's the first step to a solution.

if it's really bad, cut some of the rot off, and mix a new batch of nutes with 4-5 drops of superthrive per gallon. you should have a pretty new rootball in a couple of weeks.

find the problem, fix it. that will help you prevent future rot

kp

keep ph at 6 cut roots flush with a chemical called pithoff this is a sterilizing agent run with this for 2 days then a root booster and u will soon be ok.

i regenerate my plant so i have to do the same thing.if u can get your air pump out side your room this will cut down root temps by a good few degrees all u need is more air line .get the coldest part of the house not the fridge lol this help me out hope it helps u out good growing