DROOPING LEAVES HELP!!!

I have 12 plants, clones from the club that are sitting in an EBB system, they're about 2-3 weeks old and are sitting in 4x4 rockwool. I have had the light about 20" and on for 18 hours a day. The one thing I'm a bit confused on is how often I should water. Everyone responds to posts with different amounts but some of my OG Kush are officially DROOPING and I don't want to ruin them. I water them 2-3 times a day which I hear might be abit too much, I have a fan going but not too often right now until I get one that uses less wattage. All my other plants except for the OG are doing well although they are drooping just a bit, not nearly as much. I'm using Foxfarm nutes, and as far as temp and hum. they all seem fine. I'm just not sure if I'm watering them TOO much or not enough???? or if it is some sort of nutrition def. I'm posting some pics, any advice would be great thank. Just nothing like... it could be over watering or underwatering..... not helpful
-also my leaves are KINDA light (a tiny hint of yellow) and curling inward just a bit

Check your PH and make sure it is dead on before doing much else. You say you are using 4x4 RW so that makes things a lil easier about watering. RW hold onto water really well. Pickup a dry RW 4x4 and get a feel for how heavy it is, pretty light huh? Now pickup one of the RW blocks with plant and feel the difference. Also when you pickup block does water start pouring off of block or not. You say that you flood 2-3 times daily, that should be fine with my exp. I used to use the 4x4's but no longer do and when I used then I flooded up to 5 times a day for 15 mins a shot. I know you said temp and humidity is fine but what are the numbers?

Hum goes from 45-60, and temp def does fluctuate but there's isn't much I can do about that, they're in my garage which gets pretty cold. Lowest tho would be 50, highest 70

Also, good news the OG perked right up over night after getting the PH down, however it's probably not the vest idea how I did it, but I didn't wanna go to the hydro store and be sold on more products. I use fox farms micro brew,grow big, and big bloom. All of a sudden my ph was hella high (about three days after mixing and watering the plants). Of course fox farm also happens to sell PH up and Down for u as well. But the nutrients are what should control that the most I assume. So I checked which of the three nuts were acid or base. Found that what I bought of big bloom (nute the feed sch uses the most) is incredibly alkaline (base) and the littler bottle is acidic,
I simply added more of the acid and pure water and it leveled out. But I'm worried I could have thrown other things out of whack. But ph is most important correct?

PH is ley in Hydro but you dont want to fix with more nutes since you will most likely burn them by overfeeding. PH up and down are the key unless you go organic but which ever way you go when you are vegging PH should have a desire to drift up and visa versa for flowering. 50 IMO is way to cold, nothing below 65 for me.