Saltwater tank.

[Tropic Home]

I live 200 yards off the beach in Costa Rica. I would like to start a saltwater tank with my 5 year old and stock it with fish we can find in the tide pools. My plan is to use water from the gulf and add water as needed (weekly, monthly..???). My main question is can I use a regular hang on filter like the Tetra Whisper or Auqua Clear? It has been recommended locally that I use one that is rated twice the size of the tank (although "local" advise has been know to be unreliable). We plan on starting with a 20gallon. Any advise is appreciated.

[AABatteries]

Not sure about collecting the fish. But, do not use HOB(hang on back) filter for SW. Get live rock. And the local advise was right, for freshwater.