hello mate sorry to hear that, if its brown stuff on your roots its a water based virus called (pyphium)it kills your roots and stops the roots from taking up any nutes,you can treat it with pyphium powder you just add to your res.i just harveted my crop i thought it was a small yeild due to the cold but infact i had pyphium.
goodluck.:thumbsup::thumbsup::thumbsup: