I've been researching concrete builds lately. Just curious, do you have a way to drain part of the tank for maintenance? What some guys do on these large concrete builds is build up a wall in the corner, for example, that goes half way up. Then you can drain half of the tank if needed for maintenance like a leaky window or something.
after the tank built i did it by foam and water proof colored pool cement,and drift woods are naturel.setup not done yet.tomorrow will work on it.i think need more stones for corners.