There's another thread where I've already posted this suggestion, but in hopes that it is seen and at least thought about here we go again hehe (sorry about that if I'm breaking your rules, I just think it's a good idea :-P)
In regards to the idea of having a dome shaped piece, I think it would work fine so long as you say filled it with water as well (or left it filled with water, however you look at it), you could make it an enclosed ecosystem. Granted this doesn't le…