What is the best way to filter and heat an indoor pond? I found some plans to build a 600 gallon plywood one. I'm wanting to build it when I purchase my new house in the next few months. I'm planning on putting it in the basement, so it should be going on a concrete floor. I've seen Ocean Clear canister filters advertised, and they look like they would work, but I'm not sure. I'm really at a loss for the heater, though.