Basically, you don't...it's a sacrifice that you have to make, and one of the many things that you want to consider when deciding if you want to use a skimmer. On the negative side, skimmers pull trace elements and food particles out of the water, which can slow coral growth and starve filter feeders. On the plus side, a skimmer can keep what would otherwise be foul water under control. If you can keep water quality in check without it, then give skimmerless tanks a shot, but I would recommend a lot of experience before you try this.
