15 or 20 gallons: does 5 gallons make a big difference?

[dmiller212]

Honestly, if you're used to managing 6 gallons, you will be pleased with the upgrade either way. You probably also know just what it is that you want, given your prior experience. Totally fine if 5 gallons more isn't important to you.
As mentioned, with a tank this size, 5 gallons is a large percentage, so fairly significant when it comes to maintaining parameters.

 

[PolypPocket]

I have two cube shaped tanks and one more normal classic rectangle shaped tank. I would not buy another cube. They look cool, but unless one stacks rocks pretty high, one ends up with a bunch of space toward the top of the tank that is unused. The extra volume of water is still good, I guess, but I don't really use it....and neither do the fish or corals. I guess I really did not answer your question, but I would rather have like a 20 gallon lagoon instead of a larger cube shaped tank. The two cubes I have were the first tanks I purchased, the 40 breeder shaped tank was the last. More room to allow fish to have their own territory on/in the rocks without constantly seeing the other fish, more sand surface area for invert or fish that use the sand, most rock surface area to place coral, etc, etc.

That’s fair, and you may be right about the long being better for fish. I need to think about it more. A big part of it is space, I don’t have a lot so the cube is not only nice to look at imo but also more appealing because I can easily fit it in my studio (where I operate my business). I have tons of terrariums taking up most of the room so space is limited. But that’s not to say I couldn’t make it work, it’s just a bigger challenge.

 

[PolypPocket]

Honestly, if you're used to managing 6 gallons, you will be pleased with the upgrade either way. You probably also know just what it is that you want, given your prior experience. Totally fine if 5 gallons more isn't important to you.
As mentioned, with a tank this size, 5 gallons is a large percentage, so fairly significant when it comes to maintaining parameters.

And that is exactly why I want to upgrade. Keeping everything stable in 6 gallons is quite a challenge. Not impossible but it would be nice to have an easier time of it.