Is a filter necessary?
I am hoping that I won't have to use a filter in my new tank. I will have it seeded with springtails, and the waterfall will flow down to a pond. It will house dart frogs, but I'm hoping that with the springtails and the plants I won't need a filter. I will have aquatic plants in the pond, too. I can do partial water changes by siphoning water out of the pond when needed. I am hoping that won't even be necessary if the tank will work like a micro-climate and hopefully self clean the water.