A protein skimmer is the one acrylic part in a marine system that runs under permanent hydraulic load, so its wall and its bonded joints are structural, not cosmetic.
A reef shop in Singapore built 40 bodies from 5 mm extruded sheet at 200 mm diameter. Eleven developed a crack from the neck bond downward inside a year, all of them in tanks with a high water level.
Acrylic protein skimmer body and neck
- Body to 150 mm: 5 mm cast
- Body to 250 mm: 8 mm cast
- Body above 300 mm: 10 to 12 mm cast
- Neck height: at least one body diameter
The neck is where foam either makes it or does not. One body diameter of neck height gives the column time to drain before it reaches the cup; a short neck on a wide body produces wet foam that never climbs.
Bonding, pump inlet and cleaning
The joint at the cone is the highest stress point in the assembly, and it is also where a cheap solvent bond shows. A properly prepared joint with a bonded collar and 24 hours of cure holds at depth; a rushed joint fails at the water column.
Pump inlet detail decides noise and performance. An inlet that points straight into a wall creates turbulence and cavitation; a tangential entry with 30 mm of clearance settles the flow and the foam column stabilises.
For the panel side of an aquarium build, aquarium tank panels covers casting and bonding, and aquarium thickness the wall calculation.
Send your tank volume, target body diameter and pump spec to oversales@rpplexiglass.com for a skimmer chamber quote.
Frequently Asked Questions
What thickness acrylic for a protein skimmer body?
5 mm to 150 mm diameter, 8 mm to 250 mm, 10 to 12 mm above 300 mm. Water depth and body height drive the wall, not the pump size.
Why cast acrylic rather than extruded?
Cast sheet bonds reliably with solvent and resists crazing under continuous load. Extruded sheet is cheaper and stress-cracks at the bonded neck of a tall body.
What makes a skimmer produce foam poorly?
Neck geometry and dwell time. A neck too short for the body diameter lets foam collapse before it reaches the cup; a transition that is too abrupt creates turbulence that breaks the column.