I am starting to build my new vivarium for darts and I have some questions. I am making a small waterfall/stream that will collect in a little pool. There is a pump to keep it flowing but no filter. There will be moss and maybe one or two plants. I am worried about the water staying clean, does any one have any advice on that. Will it stay clean by itself, are there specific plants I could place into the water? I was also wondering if maybe I could put a snail in the tank? Thanks!