Second grow, comments please

Growroom- 15x20 building. Lighting- 2 400w MH on an 18/6 regimen.
Nutes- Primal Grow and Primal Bloom organics
Started 72 seeds 17 days ago from a friends grow. Looks so far like a mix of indica and sativa plants. 60 germinated and only 32were transplanted into 12oz styrofoam cups in an organic soil mix. I added bat guano 10-3-1 and wormcastings. I used BioNova Nova Roots 0-0-1 when potting per directions and I water with SuperThrive and Vitazyme for hormones, vitamins and such. the temps stay between 70 and 80 and the humidity between 50-60 percent. I have a ceiling fan and box fans for circulation. I am only using a 2'x4' space in the building, 4'x4' during flowering over 8 plants. I plan to wall up a 8'x15' section and line with visqueen plastic but at the moment I am suffering quite a bit of light loss into an open area.

My pH is pretty acidic somewhere around 6 so I am adding lime tomorrow to try and fix it. Aside from the droopy leaves and tips curling they look pretty good. N-P-K test was good, so nutes are no problem. My water is quite acidic as well, even the distilled water I buy so I guess I will have to get the chems. to adjust ph unless someone can tell me a safe home remedy, maybe hydrated lime since it is water soluble...I dunno. Insects are no problem at all, see one every 3-5 days and take care of it, I have 3 ladybugs that have ventured in and patrol the area, but they generally are inactive. I have noticed some small white spots on the leaf tops, but have not identified the culprit, possibly eaten. I plan to veg under the MH until plants are around
18" then flower under the same lights with fluro supplements. I will start taking clones as soon as I have a few good branches. I will need some help in that area, as I have not been the greatest so far. And my last crop killed over from a freeze that I wasn't prepared for so I have that taken care of. Using the guano and castings, when should I fertilize or side dress again, how do I tell without doing multiple soil tests? I am new to organics, but do pretty well with liquid chemical ferts (Algoflash 6-6-6). Off to bed, thanks for any input.