Need help with indoor growing?!?!

Hey guys I'm new to the forum I have a few question I was hoping you guys would help me out with. Okay so yesterday I finished my new grow room setup and got my clones delivered by a dispensers the strains are
(Gorilla glue # 4, sky walker og, platinum bubba, and jack herer) there about 18-20 days old they said ..This is my first time growing. My setup is 5x5x6.5 Apollo grow tent, 1,000 watt mh Apollo dimmed to 75%
(for veg and then I'll switch to hps for flower) only light I have not able to switch, 6 inch ventech exhale fan and carbon filter I have pictures of everything. Okay so the problems that I'm have are I have duct going from my house ac unit pushing cold air into tent temperatures in tent stay perfect when I have the air on but when I turn it off the temps jump to the 85's the only problem is my apartment is super cold now due to running the air in there all the time is there any other suggestions or ac or something else I can buy instead of connecting it to my house ac unit? Next thing I would like to ask will be, is my setup good is there anything I should improve or change that will make it even better. Final question will be when should I start giving my babies nutrients I included a picture of what nutrients I have I planted the clones into red solo cups from rockwool (rooted clones) into fox farm ocean forest I've heared that it's packed with nutrients and you shouldnt have to feed plants nutrients for good 2 weeks and you might burn plants if you do is that true if not when should I start feeding I've only gave them ph balanced water so far when I transplanted. Thank you guys for the help!!

Any half decent soil already has ph buffers in it so by using ph adjusters to each water then by the time your half way through flower your soil ph is all fucked.

Secondly, you give your plants fertilizer when it needs it - not based on a pre defined schedule. If the soil is good, you may not even need anything other than straight water right up until your well into the flower phase. Wait for cues from the plants. If they look healthy and perky then dont fuck with them.

If you feed nothing but that bloom fert in the picture during flower then your going to have problems. Plants need nitrogen during flower. They also need more K than P during flower.