A friend of mine has a reef tank that uses a oversized Aquatop 5oo canister filter instead of a sump for a 40 gallon breeder tank. Also has a HOB protein skimmer. He is very diligent about keeping the system clean and all of his parameters are in good shape. He wants to introduce copepods to the system so that he can have a Mandarin or Scooter goby. What effect if any will the canister filter present? Will the copepods reproduce once the goby is introduced? How often will the copepods need to be replenished? Thanks for your help.