Make sure you're measuring the PH of your water AFTER you add all of the nutes, measuring then adding later is redundant. You need to be calibrating your ph meter regularly and make sure to store it with a little liquid around the probe tip. It's bad if it dries out. You can get calibration fluid online that is always 7.0, just plunk your meter in and adjust until it reads 7.0.
You want your PH to be 6.5 in soil, not 7. Equally important is knowing the ph of your soil. If you don't have a good soil probe (like the accurate 8 ph meter) then you can gauge the ph of your soil by testing the water that runs out of the bottom. If you water your plant with PH 6.5 water and it comes out the bottom at 6.3, then your soil ph is around 6.1, ya dig?
wa
IMHO I wouldn't be tying any of those girls down unless you have a very uneven canopy or unless they're getting too tall for the tent. That 400 w light has plenty of penetrating power for plants as small as autos, even TD. Sometimes the best help is to quit fussing them.
Edit: one last thing, when I add ph up or down to my solution I add less than half of what the recommend. I can always put in another drop, but going over either direction and trying to bring it back the other way is bad. Too much PH chems fighting in the solution. Baby steps are best!
wat is fussing?

though.