A good Protein Skimmer is a must have piece of equipment for a saltwater reef aquarium. They work by removing DOC (dissolved organic compounds) which are too small for most mechanical filtration to capture. They also have many other health benefits such raising dissolved oxygen and lowering the stress levels of your tank inhabitants. We tried to list both Light and Heavy Bioloads for most skimmers. Light Bioload is a tank that is very lightly stocked with minimal feeding. Heavy Bioload is a tank that is heavily stocked with heavier feeding. For skimmers with only one size rating if it says "up to 700 gallons", that is what they will handle if they are lightly stocked. The heavily stocked gallon capacity will usually be about 25-40% less.
If you would like assistance choosing a skimmer, as the lists are extremely extensive, you can check out our Protein Skimmer Power Rankings page, which includes a huge amount of testing and research we did or email us at firstname.lastname@example.org Thank You