My old aquarium filter that was in the 300g pond just died. Is it ok to have no filter or no water movement in the pond? Too lazy and too broke to get a pond filter. There are 10 comet goldfish and about 10 rosy red minnows in a 300g pond with plants covering 90% of the top and hornwort and java moss at the bottom. At the top 60% is water hyacinth 20% water cress and 10% water lillies. I've been spraying the hose in there for a minute before I feed is that good enough?