what's the ppm? get a ppm meter and see where you are at. every day or two.

w/bubbleponic, realize that the water will get taken up by the plants faster than the nutes. The water gets evaporated out faster than the nutes are used as well, so your ppm's can creep up (especially in the summer) so be sure to add plain ph adjusted water daily to keep the plants / reservoir at the same level. You need a reservoir or bubbleponics can be a serious pain in the ass. You mention feed tubes...so you must have a res..

flush w/plain water for a day.

also, do yourself a favor and pick up some general hydroponics G-M-B so you are using something known.

PPM meter is a MUST
copobo Reviewed by copobo on . Plant Problems What is your experience level? first timer Your Equipment: .1) Type and wattage of lights. CFL's 315W .2) Distance from tops? 3 inches .3) Reflector type? enclosed reflector .4) Is there a consistent fresh air supply? Yes .5) Do you have an exhaust fan and a circulation fan? Yes .6) What are the bulb wattages, kelvin ratings, and schedule? 20 on 4 off.. my lighting is this SH Hydroponics, Inc. > Multi Spectrum 315 Watt CFL Light Bank Your medium: Rating: 5