Hey all - I'm really debating building up an aquarium in a paludarium style - land and water. I'd like to build up a mini-freshwater ecosystem so to speak. I can't seem to wrap my head around the filtration/cleaning issue though.

In my head (LOL) I can picture something completely within an aquarium, with something set up like a waterfall for cycling/filtering the water. I'd like the set up to house small crabs and/or small amphibians (maybe frogs, still researching what can and what can't co-exist, very early planning) and some tropical freshwater fish, maybe shrimp (maybe), etc. I may be over-thinking it. I'm not talking about using a small aquarium for this (no 10 gals), I'm thinking more of using my 75 gal or something similar. I'm so used to the standard filtration that figuring out this part is the hardest part for me. Would the substrate not have to remain separate from the main body of water? How would you clean the substrate? I do realize a water pump can pump the water up and through a waterfall feature, but what about filtration for it. Oie! I've been researching, but I'm feeling lost in the details.

I want to do this partly to see if I can and partly for my 5 year old who loves all creatures great and small (so much like his momma). I think it would be fantastic to create a mini-ecosystem that he can watch grow and thrive. The biggest thing for me is using real plants and such.

Any advice or ideas are really appreciated!