I'm not farmiliar with the underwater filters. To be honest, I've never seen them in use before except in terraniums. Have you considered a canister? They are silent. But you would see the hoses behind the tank. Then again, you'll see the cord anyway from the filter and heater. In regards to canisters, appropriate ones would be the Rena XP1, Fluval 204 (or 304, depending on the type of fish kept), Eheim 2213, or Cascade 700.