When I had my three, I used a filter and kept it on the lowest setting possible. My frogs never seemed overly stressed and even hung out around the filter occassionally. These frogs can be very messy, in terms of producing waste and eating habits, so either way, whether you use a filter or not, water changes will be required. Even with a filter, I did partial water changes a couple of times a week. Once you get into the rhythm, it is not that much work and the enjoyment of watching them and hearing them will be worth the effort. It's been a few years since I've had to deal with filters, so I am no longer familiar with what would be the best one anymore. However, there are several other members on this Forum who currently have ACFs who will be more than willing to help you in that area. Have you picked out any names yet?