I'm so glad that I installed the excellent Fluval 307 external filter and UV clarifier on my heavily stocked Malawi tank at home. The flow remains strong after 2 months with ZERO maintenance, I've not touched the filter since it was installed and the less you have to clean a filter, the more effective it's beds of beneficial bacteria are at removing ammonia and nitrite from your water. If you can afford one, it's a wise choice to setup an external filter over an internal filter! #filter #cichlid