You want absolutely NO light in your reservoir tank! That can cause algal growth and you do NOT want that. As long as your airstones are pumping away, you really shouldn't have to worry about the roots. Keep your pH where it needs to be, watch your ppm's, flush often, watch for bugs, and don't worry about H202.

Maybe Shake will chime in with some other useful information.
SauceeMcGee Reviewed by SauceeMcGee on . Brown tips and edges, pictures and data sheet I have brown tips and edges burning but my stats are at what the makes of my food say... So I am not sure it is not a full blown wide spread problem just here and there it pops up and I don't want it to become a full blown problem. Problem Sheet First Hydro Grow Your Equipment: .1) Type and wattage of lights. (MH, HPS, CFL's, tube fluorescents, LED's) 300w HPS 1ft from tops, 300w CFL just above the plants .2) Distance from tops? Rating: 5