Help! Leaves yellowing and curling

Hey,
First time grower using a stealth hydro bubbleponics system with the multi spectrum lighting configuration (although I only had the multispectrum light till a few days ago, got the flowering but the veg is still backordered). Its about 2 weeks since I planted the seeds and everything has been going great until about 5 days ago when the leaves started to curl upwards and become disfigured. Since then some of the leaves have begun to get yellow at the tips. One seems to have some very faint small brown spots. I just raised the lights to where they can be seen in the pictures from about 3-4 inches above the plants. The Temperture is generally between 73 and 80 degrees and the humidity inbetween 40-50%. I just changed our batch of water/nutrients for the first time about 2 days ago so maybe that will show signs of better health in a few days but im not sure. I just checked the ph and it is about 6.25. Anybody know what to do? Check out the pictures and let me know if some better angles would help because the curling twists in all directions. Please help!

Yes.....drop your ph to 5.6-6.0 and don't let it wander outside that range. i think your problems will go away if you do. What kind of nutes are you using and how many ppms?

Thanks for the advice. Im using the GROW nutrients that came with the stealth hydro system. They come in premeasured baggies and it says to only use a full sized one when the plants are about 6-8 inches, so I only used about half a bag. The nutrients contained are as follows:

NPK: 10:5:14
Calcium: 6%
Magnesium: 2%
Sulphur: 3%
Iron :0.12%
Maganese: 0.05%
Boron, Copper, Chloride, Molybdenum & Zinc: 0.01% or less