Yes on the holding pool for a bog. The filter I'm not so sure about. You only need the bio filter for the fish and with the size of the pool I'm guessing that you could get away without one if you were to keep the fish load low. The mechanical filter is what would keep the pond clean and you would need one of those. The bog idea might work with enough material put into it. Is it possible to pump into the bottom and let the water flow out the top?You will be fighting green water no matter what type of filter that you use. I'm not sure if you could get a UV light big enough to handle the volume of water in the pond buy you should look into it.