necessary? No. You’re pulling out your dissolved organics by skimming. Shut it off for a week. Your corals if anything are starving with no detectable nutrients. Skimming is for folks that have the opposite problem that you are.is a skimmer necessary in a 30 gallon? I know some people said it wasn’t. I’m not using one on the 10. I was scared to not skim with the corals in the 30 LPS ones