I don't pretend to be an expert, but I do have some knowlege in this field. I owned a pond store for several yrs and "I'm also a master gardener. I try to keep things low maintenance and eco friendly. Nature is my teacher. I don't recommend UV lights...ever. They kill bacteria...good and bad. If you want a "spa" build a spa. If you want happy fish and plants...go natural. JMO