EWC TEA - roots black seaweed? pictures inside

[SRG CPT Weed]

Been fighting Algea,first dwc grow,so everything was clean,new water,dead roots 60% removed,no PH swings,but there was no new growth,roots were brown still and as I said no new growth,sO I thought this tea will give fatal kill and my plants will recover,so..
2 days after ewc tea,thats how my roots look like,now they turning even black lol!!

For ewc tea used - 5 gal bucket,biohumus worm compost,mollasses/white sugar for feed.