are you saying you see larve n roots?

you seen bugs? black gnats?

if it's larve, say gnat, thrip, or mite, a simple peroxide flush will kill and add mtch needed O to the roots. 99 cent bottle of3% will do. in co~co i added 2tbs(24 1/2ml) per gal. it should be fine for rw, but check it out 1st. I'm just guessing.