75 gallon vs 90 gallon

[ca1ore]

90 versus 75 .... go 120. 24” front to back makes a huge difference.

 

[Imaexpat2]

There will be very little difference in the two other than initial purchase price. Maintenance will be the same, very little if any difference in cost for equipment to run either, what would work on the 75 will most likely work over the 90. That being said I would default to the 90 over the 75 for the extra water capacity if nothing else, especially if your a "Stick" dominated tank kinda guy like I am. That 3 extra inches will make a noticeble difference!

 

[SpecificGravity120]

I say go with the 75g tank. The only difference between the 2 tanks is the depth... the other parameters are the same. All that extra space above the rocks isn't totally used by fish since they all stay near the rocks.

The fish you can keep in a 90g aren't any different from the fish you can keep in a 75g tank.

Agreed. The extra height is usually wasted space. Only real advantage is the extra 15G of water providing a buffer for better safety margins on water quality, but you can easily add that via a sump.