Why do my plants appear to be wilting? +rep

Using General Hydroponics micro gro and bloom, + floralicious gro
Pro mix soil
I was told the strain is green crack, but isnt that a sativa? These are definately indica dominant so....
1000W hps in a 6" cool tube
temps 26C during light on and about 21C light off
humidity 30-35% sometimes dropping to 25%
I water every 2 days, when the top inch or two of the soil is dry, and use PH 6.5 water as a foliar spray about twice a day, some appear to be wilting, one worse than others. The one that is wilting the most is also a bit lighter in color than the rest of the plants. They all receive the same feedings. Any help would be much appreciated

Ill be watching this for an answer to mine as well!

I think it is over-watered so i'd say water it every 3-4 days

I'll leave them alone for an extra day or so.
I'm having trouble committing to this being overwatering....as I do not water to the point of runoff, and my hygrometer says the soil is dry right now, even deep under the plant. (although it still feels moist to my finger an inch or so under the top of the soil)

your deffinately over watering man. i sometimes only water once a week and my plants love it. your plants will have an easier time trying to survive a little dry then flooding them