Plants growth stunted and leaves browning and dying off.

So I'm growing two plants as a test, and was very encouraged with how healthy they were and how well they were coming up. They were in small starter organic pots, and under a regular florescent tube. adding a weekly shot of miracle grow.
I moved them into a nice 4x4x6 grow tent, with a "Hydrofarm FLCDG125D Fluorowing Compact Fluorescent System", into larger pots , and an auto waterer (after I realized (or at least was told) that I had been watering them too much. I found the leaves were browning and dying. It was suggested that the PH may be too high, so I checked that and found it to be almost 8 (Perhaps I kept the Miracle gro going too long?), I added sulfur to bring it back down, but it wouldn't move much. I transplanted them into fresh untreated potting soil and it's down to a little above 7, but the leaves keep dying off.
At this point they have been the same height for a little over a month. They keep growing new leaves, but as quick as the new ones come in, the lower ones die off.
I also don't know about the temperature. Somewhere I saw you don't want it too warm, around 70°, another source I just saw today said it should be 80-90°?? It's usually a little below 70 in that space.
At this point I'm wondering if there's something else going on? I had the light about 7 inches above the plants, but recently moved it higher as someone said that might be the problem.
I'm also wondering if these have 'used up all their energy' trying to stay alive, and if I should just give up on them because they've past the point of no return or something? Or if I get it figured out will they be OK?
I remember tossing a few seeds into a field years back, and they came up just fine! This seems a lot harder, with a lot better environment, so I'm kind of at a loss!

Any input or recommendations are much appreciated!

IMO... ...it's time to start anew.

Potting soil and miracle grow wont get you very far.

Here's easy mode:

2x White 2-Gallon Home Depot Buckets

1 brick of Coco coir

1 bag of rockwool croutons or pearlite

1 bag of GH Maxibloom (for a single-fert solution - use lucas formula)
... or I recommend...
Future Harvest Starter kit (and follow this feed schedule)

1 Roll of fiberglass screen from Home Depot (and some silicone adhesive)

[HR][/HR]
Cut a single 1-inch diameter hole in each bucket 3 inches from the bottom. The bottom of these holes should be 2 inches from the bottom of the bucket.

Cut out 2 inch squares of fiberglass screen and glue them over the 1-inch holes in the buckets to create a breathing hole that doesn't let your medium fall out.

Soak the brick coco and rockwool (or pearlite) in ph 5.8 water for a couple hours.

Fill the bottom of the buckets with the pre-soaked pearlite or rockwool croutons so they just cover the breathing holes you just made. Fill the rest with the coco.

Toss in your seeds, and water whenever the top of the coco looks dry and the buckets feel light. You'll probably water once a week at first, and about every other day during bloom. You'll get a feel for it quickly.

I'll add in, that a little below 70 is too cold. 72-78 is a bit better.

Also, flushing with a Phosphorus sourced Bone Meal will bring the pH back in range.

Thanks a bunch guys! Since I need to restart, should I retry with the "Stealth Hydroponics Bucketeer DWC Kit" that I got, or is that going to add another level of complexity? I originally tough that might be easier, but as I read more I am beginning to think it might be more complex than the straight forward system you lay out above! Let me know what you think and I'll get started again! Thanks again!

Don't waste your time with recirculating hydro this early in the game. I've grown for many years and after running it all, I highly recommend the K.I.S.S. of coco+hempy. At the scale you are growing, you won't see enough return on the hydro to make it worth the extra work. Trust me on this.

You can get just as good results running to waste with Hempy buckets and coco. It's hydro anyways, but just as easy to manage as soil.

Yea, that's the feel I was getting.
BTW, what's the best way to get the water to 5.8ph? Ours is a bit high, so i want to be able to readily get it down to where I need.
Thanks again!

I use PH Down when needed.

OK, some folks had said use vinegar, so i wanted to make sure. On the fert, if I go with the single for my first (or I guess second) time out, just to double check, I'd want to use the MaxiBloom the whole time, and not the MaxiGrow?

Thanks again for all your help!

With Hempy, I believe you use maxibloom the whole time. Search the forum for it and you'll find some good info. I've never used it, but some guys swear by it.

Make sure to buy some CaliMagic also (or other calcium-magnesium nutrient) if you are growing in Coco.

So trying to revive these, and get an idea of what I did wrong so I don't do it again, I added my "Hydrofarm SBM150S 150-Watt Mini Sunburst with HPS Lamp" thinking it would add the element of the warmth from the ballast. The Temp stayed above 73° (up to 76°) but the leaves wilted further almost immediately and some of it turned kind of white (not burned and crusty like they were, btu just wilted like they get after you pull a plant out or a leaf off). I thought maybe that was too much light with both, so i disabled the florescent, and from there the wilt turned to dry and crusty. Also, the basil I have in there grew like GANG BUSTERS! Any idea what that might be? I want to get any problems worked out before my new supplies arrive and I start over, so I appreciate any further advice! Thanks!