you wont have light problems those bulbs and that setup is perfect and yea add very little nutes it may look unharmful but what ever it sais in the back does it. i was adding ph dropper in the water the other day.. it has sulfuric acid in it and never use that crap not even if u ph is pure alkaline its very harmful and burns leaves after using it i could feel little bees stinging my hands i washed them but at night i saw one part of my flesh on a finger had melted off haha sounds gross but its very very small u can see some pink from under the skin