Bio-pellet Reactors: whats good whats bad

[Reef Pilot]

I am using a Vertex UF-20. Very happy with it. Tall, so takes a small footprint. You need to use a screen mesh instead of the sponges inside, so you don't get clogging. I have it T'ed off a return pump right now. It has a ball valve on the input side so easy to control exactly the amount of flow you want, to get the best tumble. Totally maintenance free, no cleaning, only have to add bio pellets every 3 months or so.