75 gallon over 90 gallon !

Go with the 90. You can fill the space between the rock and the water surface with nice SPS corals. Lighting will not make that big of a difference. JMO

 

There's always the 120 ;D

 

Everyone is making really good points, I am more indecisive now than when I originally posted this.

 

Haha, it makes your head hurt huh . I was like that when I was trying to decide what to get. Also try to factor in what types of fish you want to keep so if you're looking to keep Tangs or larger fish, you'll really want to go bigger, bigger than 90g even. If you want cool smaller fish, they'll do fine in the standard 4ft long or cubes. I have a colorful mix of smaller fish that I keep in my 70g. I would never do a Tang in it, but there are lots of great fish you can keep in a smaller dimension tank.

Are you getting a drilled tank with an overflow?

 

MoJoe makes a really good point. Put down on paper what you want/plan on putting in your system, and possibly that will dictate the size you need. If you want to keep tangs, 90 is bare bare minimum. What kind of coral do you want, and are they fast or slow growing?

Only you can answer what size you need, and what you want should dictate the size.

 

My 150 is 48 x 24 x 30 LDH. My 90 was 48 x 18 x 24

 

a 90 is no better than a 75 for tangs. Height doesn't really count towards swimming room mostly only length does, but depth may also, at least to an extent, but it depends on the rock work. If there is room to swim corner to corner, this makes a big difference, so, a 75/90 could have more swimming room than a 120g, if it had fairly minimalistic aquasaping and the 120 was packed full of rocks. I wouldn't say a 120 is enough for a tang and a 75/90 isn't, it depends on the layout.

 

Hey, I'd deal with wearing snorkeling gear for something like that j/k

I do agree with the height thing, it produces a more "showy" tank. I just don't like the 90 in particular. Same thing with a 55, the ratio between the depth and height just isn't enough. No right answer though, everyone's opinion is right for them.

 

I am definitely getting a tank drilled with an overflow, and I definitely want a Tang which is why I was considering a 90, thought the bigger the better, but i really think I like the overall look of the 75 better...........I am so friggin indecisive.

 

Do you have enough room for a 100 gallon? The 100 gallon is 2 feet longer than the 75/90