I'm planning to build a reef in a picture frame. The tank itself will be acrylic for light weight. I'm thinking 24 x 15 x 5 ish. That'd be about 7+ gal
. For filtration I'm thinking a nano protein skimmer and an under-gravel system all hidden by the frame. Lava sand substrate would be light weight, and porous for water flow to the filter. It will be roughly about 70 lbs with water and equipment. A TV wall mount could be use to attach it to the wall. I'm still trying to come up with a light weight background that I could stick critters to. Taking all suggestions.
I should also mention I'm new to salt water. Fresh water with a similar design would be much lighter and cheaper.