@ Mike, the tank looks great!
I would not worry to much about the weight. We have been hanging much heavier german metal halide fixtures for ever without issues. Obviously you need to be careful and anchor them correctly. If you can not find a stud, you can use 1/2" spring loaded metal butterfly anchors (Toggle Bolts).
These guys tested the 3/4" with downward (Shear) pressure and it failed at 300+ LBS. with 1/2" drywall.
http://www.todayshomeowner.com/testi...cture-hangers/
That capacity will NOT be the same with tension pressure(like hanging chandelier) but it can easily hold half that amount. I have personally tested a hang kit with these and it help me up no problem.
What important is the your drywall is sound. Do NOT hang if the drywall has been repaired.
Here is the shipping weight of each fixture…
ATI2601 ATI 24" 1x75W LED & 4x24W T5 LED 17.0LBS
ATI2603 ATI 24" 1x75W LED & 8x24W T5 LED 27.6 LBS
ATI2605 ATI 36" 2x75W LED & 4x39W T5 LED 24.0 LBS
ATI2607 ATI 36" 2x75W LED & 8x39W T5 LED 39.0 LBS
ATI2609 ATI 48" 3x75W LED & 4x54W T5 LED 31.4 LBS
ATI2611 ATI 48" 3x75W LED & 8x54W T5 LED 51.0 LBS
ATI2613 ATI 60" 4x75W LED & 4x80W T5 LED 39.0 LBS
ATI2615 ATI 60" 4x75W LED & 8x80W T5 LED 63.3 LBS