1, go here and read and study :
https://www.rollitup.org/hydroponics-aeroponics/7897-stealth-hydro-bubbleponics-systems-98.html
2, and go here and read and study:
SH Hydroponics, Inc. > Growing Instructions
3, you got some bad stretching, due to lights being too high. This is NOT when you
want stretching. Those babies need a saturation of light. Get some toilet paper tubes, (without the paper on them) or cut a paper towel tube in thirds, and use them to support the babies b4 they fall over. Just place them over the plant, so the top of the plant still gets light and the sides keep them from falling over.
4, lower your lights, and if you are using CFLs, lower them to two inches above the plants. If you have HID lights, you still need them lower.
5, Stealth Hydro sells a foilage spray. They and I reccomend a daily spray, to twice a day spray, while still in VEg stage.
6, they are ready for 1/4 strenght nutrients.
7, take some kind of lid, like a plastic lid for a plastic cup, or use a paper plate or a styrafoam saucer,and make some covers for your cups so that LIGHT doesn nto penetrate the rocks and cause algae in the water. (everyone does it and there are dozens of BUBBLEPONICS THREADS with pics,that show the covers in the pics.
8, pH? Read up or google pH stablized, or pH stablization. You should take your water and test it, firt and se what you have to wrok with. then pH it to around 5.8. 5.6 to 6.2, is fine, but get the water at a desirable pH, THEN, add your nutes.
9, a trick some use is add a 1/4 teaspoon of baking soda to one gallon of water. That will wreck havoc on the pH, BUT you then adjsut it up and down with pH UP and pH Down to the desirable pH. he baking soda in it will keep it from jumping so much. You still, everytime you add water, will have to adjsut it, but only weekly, or twice a week. Never adjsut it int he tank, unless you jsut absolutely have to.
I'l be back here soon to check on you.
God's Peace