I have a 75 and would like a bigger tank but the location of my tank does not allow it. If I were to suggest something it would be to get a tank that is 24" deep. 18" just does not bode well for aquascaping. I saw a 4ft 120 that was 24" and it looked nice and deep. A 180 would be awesome if you had the room.
I keep a YT, a mandarin, a royal gramma, 2 damsels, a yellow watchman goby and a percula clown in my tank. I also have softies, LPS
corals. I also have a 75 gal
sump, a 20 gal
refugium, a 20 gal
and a 10 gal
frag tank that is plumbed into the main system. Water volume is a good thing
*180 gal Display, 100 gal basement sump, 33 gal refugium, 3x250 MH, 2x160 VHO actinics, zoos, some softies, LPS & lots of acros and other SPS.
*100 gal prop tank plumbed into main system w/ 2x96 PC lights and 1x150 MH,