That's the way I run my pond filter - dirty pond water pumped to the bottom of trash can - then flowing up thru the filter media - to the exit port on top. Works like a champ and I only have to clean it a couple of times a year. I had noticed at one point a foul smell from the water at the bottom of the filter when cleaning - apparently there were some dead zones of water that were not flowing and hence, stagnating. I bought an air pump and placed a couple of large air-stones in the bottom of the filter to oxygenate the water and keep it stirred-up and problem solved. That filter set-up will last you many years...No problem, you don't necessarily have to use a bucket either you can get creative with it. My pond is a little over 300g and this is what I'm running now with a 1000gph pump. It's a garbage can. It stays crystal clear with 6 turtles and fish.View attachment 301275