I really love mine. It works great. You just have to make sure that you have plenty of mechanical filtration in front of it. Small gunk passes right through and larger things get caught and sit on the top. It's not fun to siphon stuff out.
Also make sure that you don't over do it on the pump. They really don't require very much flow for full fluidization.
lifeguards model 300...I figured I could always use it down the road on a bigger tank...I'd like to take off the hang on the back whisper I have on the 75 and put a sand filter on it.
That's a good question.....for a fluidized bed filter how big of a pump DO you need to run it? They never give you any idea when you look at them at the LFS or online.