your tank size is the size of my pool! I was thinking to convert it into a fish tank ... we never swim in it! the only thing is that we have pretty cold winter in there! so the best way is too did because it dose'nt freeze under ground. lol... Im gonna make some money before and after that my plan is about digging a big hole about 12 foot deep made like a pool withe resin panel or cement fondation... and into the center place a glass or acrylic tunel that will form a T with one access and 2 dead end... If i have lil more money I want to cover it with glass floor and make a room over the tank.... imagine yourself sleeping over sharks! or working if its my office! ... (I plan to make an automatic trap to drop my competitor into the tank! (Joke)