[sunce_22]

I run two 20 Gallon Nano tanks and a 10G Nano tank without any filters, skimmers, phosphate reactors, sumps or anything. Simply LR and powerheads.
In my 10G: I have 12 pounds of live sand and 14 pounds of LR and one powerhead. The bioload is very small: 1 small damsel, 1 mantis shrimp and a small clean-up crew.
My 20G: Both have approximately 15 pounds of live rock in them. One tank has 1 pair of Naked Clownfish and a Cleaner shrimp and a clean up crew
The other 20G has a pair of clownfish, a sea urchin, a mantis shrimp (inside a critter keeper) and a clean up crew.

I have never had a problem. I only do water changes about 20 percent once a month or so too. Everything is just healthy and happy.

Im no expert though, all I know is that is what works for me. My fish are thriving, corals are growing and there isn't any algae so I have no complaints.