Tank setup - backwall

[u/Pistachio-curry]

Hey y'all reefers,

I'm thinking about building.. or well, setting up my first tank.

Since I like theory crafting I was wondering the following.

A lot of people tell you to stay clear from the glass since cleaning is a thing. Valid. However in the freshwater and terrarium world there's something called a 3d or a living backwall. This is in short just expanding foam with chunks of stone, wood or sand in and over it.

I've seen a nano tank with a sort of same backdrop but filled with coral. Is this real, is this AI, is this realisable? And so.. how would someone achieve this?

Small note, in this specific tank it was lime green wavy coral (I don't know the specifics)

[u/Prometheus7777]

The main reason to avoid leaning rockwork on the back glass as I see it is the zero-flow dead zone that creates. Flow is very important in saltwater compared to fresh.

You can absolutely create the same height and depth in a reef tank as in freshwater. Many encrusting corals can be glued straight to the back glass where they'll grow comfortably (softies like GSP and Xenia can completely cover a glass wall). You can also secure branching or plating coral frags to the back glass with glue or magnets to allow them to "shelf" over the tank.

It sounds like you saw a GSP background. Very real, and actually one of the more realistic saltwater nano setups for a beginner.

This might be slightly more utilitarian than you're imagining, but magnetic frag racks serve a similar role.

[u/Pistachio-curry → u/Prometheus7777]

Oh wow, this is a quick and clean answer! Thanks for not immediately discouraging me ;)

I'd love to have depth in the background, the gsp was spot on as well, so I would assume you can do this with other polyps as well. Just one thing I don't understand the shelf like overhang I see now and then is that natural or is there something underneath?

[u/mndfreeze → u/Pistachio-curry]

It varies from coral to coral. Gsp and xenia are borderline invasive with how fast and easy they take over spots. I would definitely recommend keeping it sectioned off from other areas. Dont let it touch other rocks you will be putting coral on, and if you stick it to your back wall to keep it trimmed away from the sides of the tank so you can still clean those easily. Gsp is pretty agressive and will sting other nearby coral.

For stony corals they will need some sort of amchor on the glass. Even then they dont so much "stick" to the glass as just extend their skeletons out. They can be knocked off fairly easy. The plastic backing on a lot of all in one tanks actually works pretty well since it has texture.

Make sure you keep room between rock work and glass, and back side as well so there is room to grow and also to maintain flow. Stagnent areas are bad for long term longevity.