This will feed a small waterfall. I had an 800 gph pump and I just broke it like an idiot. I am told that the drip or trickle style biofilter is best. Does this actually sit outside of the pond? Do I need a seperate pump for that and another for the waterfall? I had a beckett biofilter before and it was fixed and submersible. I am told that it is junk. Please advise a decent setup I can get at Home depot or off of amazon.com. Thank you!!!