TANKS & FILTRATION

Protein Skimmer

Foam fractionation unit that strips dissolved organics — a marine tool, not a freshwater one.

Maintaining stage Tanks

Unplug before servicingHands out of the water firstDrip loop on every cableTest before you dose30 ppm CO₂ ceilingCycle before stocking

Tanks

Technical line drawing of Protein Skimmer

Specification
Application	Saltwater / reef only
Drive	Venturi, needle wheel or air stone
Rated volume	100–1500 L
Body height	30–70 cm
Power	8–40 W
Collection cup	Removable, 0.3–1.5 L

Technical parameters
Freshwater suitability	Not effective
Marine tank sizing	Rated 2× display volume
Skimmate production	100–500 mL/week
Break-in period	3–14 days
Cup cleaning	Every 3–7 days
Water level sensitivity	±1 cm changes output

A protein skimmer injects air into a column of water to create a dense foam. Dissolved organic compounds — proteins, lipids, and the waste products that break down into ammonia — are surface-active, so they cling to the bubble surfaces and are carried up into a collection cup and removed as skimmate.

This works because saltwater has the surface tension and ionic strength to hold a stable foam. Freshwater does not. A skimmer on a freshwater tank produces a thin, unstable foam and removes almost nothing, which is why you will not find one on a planted aquascape.

In a marine or reef system the skimmer is arguably the single most valuable piece of equipment, because it removes waste before it becomes ammonia rather than after. It also aerates aggressively and stabilises pH by driving off excess CO₂ — which is the opposite of what a CO₂-injected planted tank wants.

Safety and welfare

Skimmer pumps run with air and water together and can run dry if the water level drops. Use an auto top-off or check daily.
Skimmate is concentrated organic waste. Empty it down a drain, not into a garden or a sink you use for food preparation.
Unplug before removing the collection cup — the pump can splash.

Using it well

A new skimmer needs a break-in period before it produces consistently. Do not adjust it every hour on day one.

Wet skimming (more water, lighter skimmate) removes more total waste. Dry skimming (darker, thicker) removes more per volume. Pick one and stay consistent.

If output suddenly stops, check the air intake for salt creep before assuming the pump has failed.

Belongs in

Reef tanksFish-only marineMarine sump systems

Worth knowingNot used in freshwater planted aquariums — freshwater foam is too unstable to fractionate.

Note. Parameters are conventional ranges across the category, not the claim of any one manufacturer. Nothing on this page is for sale and no outcome for any plant or animal is guaranteed. Simulator output elsewhere on this site is a simplified model, not a measurement — confirm everything with a test kit and the equipment's own instructions.

Protein Skimmer

Using it well

Belongs in

Works alongside