Ok its dark now.... very tiny bit getting through the medium but I think its fine (Ahh I guess ill add small black plastic discs on top of the medium). Changed water out added full str nutes and 60ml H2O2. I think the smaller plants can handle it if not I can remove them and put them in a seperate res. and flush at first signs of burn. PH sitting at 5.8 and TDS is 1050 PPM. Its distilled water.