All skimmers work in the same way, but there are different designs that have developed over the years. These include co-current, counter-current, venturi-style, and ETS skimmers. Each works in a slightly different manner.
Protein skimmers are often a good choice for keeping your saltwater aquarium clean. Besides primary biological filtration, foam fractionating (better known as protein skimming) is the most important aspect of any healthy marine system.

Although there are systems that claim to be “skimmer-free,” for most of us, dissolved organic compounds (DOC), phenol oils, and other yellowing agents are a nuisance. Only active protein skimming can eliminate the need for these.It is also important to understand that different manufacturers put their own twist on the basic design.
