i dont use a filter either. i use my skimmer and bi-weekly water changes and that is it. water is clear and very few particles. i have 3 astrea snails, one cerith, 4 small hermits, a few brittle stars. no problems. in fact, the filter may be just creating nitrates for you. if you have clams and a bunch of filter feeding critters, it may not be a bad thing, but for a lot of fish and inverts, nitrates are a no-no.