Need to fix my DWC roots!! (pics)

Ok so here is the rundown........ A while back i bought 4 black 20L buckets(5gal). They had both black and white buckets but only the whites had lids so i grabbed 4 of the white lids and have been using them....like an idiot. Im currently growing 2 autos (hobbit & mikromachine) and all was going well until the last couple of days where i started seeing this dark shit forming mainly at the top of the root ball and light green algae on the underside of the lids. I rectified my light in rez problem with some awesome reflective coated bitumen tape, washed my buckets with h2o2 and added 2mL per 20L of 50% hydro grade h2o2 to the rez's. Ph is steady around 5.8, rez temps a little high at around 25C (high 70'sF) feeding 4/5 strength, changing water out weekly. Is there anything else i should be doing to rid this horrible shit from my roots? I have tried researching a h2o2 bath but have come up with little information. What sort of dilution of 50% peroxide and for how long? The are 3 weeks old from seed today. Thanks in advance

Bump. I really want to get this sorted asap so any words of advice would be appreciated

I'd give them a haircut and put them in soil.. But that's me I guess

That wont be happening... i have been adding 1 ml per 10 litrs of h2o2 daily and my roots are looking only slightly better. Plant growth has been quite good though ive seen faster in dwc. Should i just keep adding peroxide daily at this rate?

Good to hear they are doing better - take pics when ur done - I'd like to see outcome.

Post in Hydro for better answers

A "friend" of mine used to run a DWC set-up... he would use the 3% medical grade h2o2, the stuff you buy at the pharmacy... he'd add like ten milliliters everyday to a 4 gallon res.
by the way... I've never seen a problem with root rot or anything else in that set-up