round 2 led dwc grow

Hello everyone I'm doing my second try at dwc. Any help wanted.
Equipment
4x4x7 tent completely lined and taped sealed shut with 1"insulating Styrofoam
1000gph water pump for 8" ice box and nute chiller coil
8" inline fan
65 pint dehumidifier modified for water chiller
4 3.5 gal buckets with 6" net lids (making expansions so I can make into 5 full gal without replumbing)
Rubber maid for rez 14 gal I think
400 ghp recirculation pump
Ucdwc design didn't exactly follow the retail one 1 " thru buckets 1/2" return to rez
70 lpm air pump 4" disks in buckets 6" large cylinder ones in rez two of them
Advance nutes full line
Exhale co2 bags 2 those co2 meter ppm holds between 1400-2000
1 300w led 100x3w 8 band
2 21x pro hydro grow led 36w ea.
Plants
2 pre 98 bubba cc 1 week old
1 Afghan kush 3weeks
1 critical cali mist 2 weeks
Ph sits at 5.8-6.0
Ppm right now just changed water 1200
An grow micro bloom, b52, voodoo juice
Daytime room temp 74-78
Nighttime 74-66
Any advice is greatly wanted

Oh and a cpl in soil but there leaving soon lol

When you listed the plants ages, I presume you're talking weeks of veg, not since germination?
If it's from germination, careful with that high PPM.

Are there bubblers in each bucket also or just in the main rez? I also think that your PPM levels are on the insane side, I would be at 75 PPM if they were 2 weeks from seed not in the thousands, that's crazy pants!