Can a protein skimmer be too large for your setup? Yes, it most certainly can. If the skimmer is too big, it will have a hard time maintaining the rate of nutrient removal. Nutrients will still be removed, but it will require a larger bio-load to maintain the skimmer’s performance. Additionally, the foam head will be unstable since the protein skimmer’s neck will be too large to maintain a thick, frothy foam level.