Filter/Amphipod problem

I have a 20gallon reef that is about 4 mounths old. Its doing pretty well and one of my filters is the Bio-wheel 150, which i change out at the end of every mounth. I put the old pad in a bucket when it was time to change it but didnt throw it out intill the next day because I forgot. When it was dry I looked at the pad and it was doing its job just pulling out the wrong thing. What I saw on the mesh/pad part of it was hundreds of trapped Amphipods. The pad was almost covered with them. I have a madarin and just like every madarin it only eats amphipods/copods. Should'nt everybody have this problem? please help.

 

Amphipods love to eat the organic materials that the filter collects, so that's why they were all over the pad. I don't think they stay on the filter pad all day, so I'm sure they are in your tank a lot and available for the mandarin to eat.

 

There are a large number of people that don't use power filters/biowheels on reefs as well. They're generally unnecessary if you have enough rock in the tank to provide the surface area for the nitrifying bacteria to grow.

20g is very small for a mandarin that isn't eating frozen food. I don't think the filter is going to be your problem. In the long run the mandarin is probably going to exhaust the natural supply in the tank regardless of whether you have the filter on or not.

You could look at supplementing the pod population with bottled pods, or look into culturing your own population of pods to feed to the tank every day.