Ok, well every size tank I've been considering in the last week is currently available reef ready for a $150 purchase price (no kidding). SO... what you think...

75rr (tank, stand, canopy)
90rr (tank stand canopy)
100rr (actually 60x18x20, 2 stands, tank, drilled 55 that was going to be a sump, ETSS reef devil deluxe, and ugly @$$ canopy with t5 retrofit)
125 rr (tank stand canopy).
Oh with a little side wheeling and dealing I can buy the 75 or 90 and trade for a 110 high.

Considerations:
1.) I want to go with t5 for lighting to minimize electricity hit. (I currently I lack interest in the 1000 dollar DIY LED builds)
2.) I actually already have a 36x14x10 acrylic sump that I can redo the baffling in.
3.) I have no clue how to actually determine plumbing needs of return pump sizing.

I think I'm leaning toward the 90.

Hell of a deal no matter which you end up with! Go for it!

get the 100g!!
good water volume!
it comes with the t5s you want
your fish and tang will have a sick amount or space to swim
you can keep buying more Corl like you always do
only down side is that youll need bout 120-130lbs of rock and sand.....
but im sure that if you found all those tanks that cheap you can find a deal on LR and sand!

100G!!!!!

I'll choose the 100gl too, i think thats a perfect size for SW..!

For $125 I would go more with 100 gal or over. 75 and 90's I've seen for under $100 on CL from time to time but that's here in Richmond Va.

Getting them under 100 isn't the issue it's finding one reef ready for under a 100.

Bigger is always better in a reef or saltwater for that matter but you already know that. you will need to measure the overflows on your tank then you need to take into concideration the head preasure you'll need for the pump size which is the distance from the sump up to the overflows. I am using a 1800gph on the 180 I upgraded it to a 2600 but was unhappy with trying to adjust the valves constantly so I went back to the 1800.

I wouldn't go for a 125 only because they are so narrow on the flip side the taller tanks are a pain to maintain unless you dont mind snorkling lol honestly the 90 has good dimensions without being to narrow or too tall thats why I chose the 180 24"x 24"x 72"

yeah I'd eliminated the 125 and 75 due to being shallow. I'm probably going to end up with the 90 depending on the stand.

no matter what you choose the price is right!
even if the stand is junk bust a DIY onit and spunk it up a lil!

I would go for the one with the largest footprint since all are about the same volume.

Went with the 90. It was a running system 3 days ago. The others have all sat dry for a year at least, and I didn't feel like redoing the silicone. Plus I wanted the depth.