Best protein skimmer for a Waterbox AIO 20 Cube
A protein skimmer pulls dissolved organics out before they break down. Rate it for your water volume — with a little headroom for bioload.
Look for a skimmer rated to at least 62 L, ideally ~90 L, for the Waterbox AIO 20 Cube (62 L / 16 gal net volume). Size to how heavily you'll stock, not just gallons — bigger isn't automatically better.
Showing the 12 best-fit picks. 45 more protein skimmers in the catalog — see all protein skimmers.
Frequently asked
What's the best protein skimmer for a Waterbox AIO 20 Cube?
Look for a skimmer rated to at least the Waterbox AIO 20 Cube's display volume, with enough physical clearance for its sump/chamber — see the ranked picks above, checked against its actual dimensions.
What size skimmer for a 16-gallon reef tank?
Rated to at least 62 L (your display volume), ideally ~90 L for a normal bioload and some headroom.
Can a skimmer be too big?
An oversized skimmer can run inefficiently on a lightly-stocked tank, but it's a much softer problem than an undersized one. Match the rating to your planned bioload, not just the tank's gallons.
In-sump or hang-on-back (HOB)?
In-sump is the norm once you have a sump — quieter and tidier. HOB skimmers suit all-in-one (AIO) tanks without a sump. Check the skimmer's footprint fits your sump's skimmer chamber.
Guidance only — sizing is a starting point; verify specs with the manufacturer before you buy.