I think the better question to ask is what's your water change routine, and what are your average nitrate levels. The purpose of bio filtration is to keep ammonia and nitrites at 0, and that's the easy part. As long as you have plenty of water moving over some sort of media with enough surface area, you'll never see ammonia or nitrites.
The challenge is keeping up with the nitrates produced by the filter due to these big messy fish. If you can manage to keep nitrates at near zero levels, you'll have happy and healthy cichla. Keeping them in constant 40-100ppm of nitrates is not ok IMO. Nitrate is like a poison. Would you want to be exposed to second hand smoke every day all day?
True true. Filtration and UV does not replace WC. However, a good filter IMO should be easy to maintain and efficient. Being exposed to second hand smoke is something we have to deal with because it's going to be there but if you can clear the air quick and easy, people will be a lot happier.
