Gyre-Style Wavemakers: Wide Laminar Flow for SPS Reefs

Most people's first wavemaker is a small propeller pump stuck to the glass with a magnet, pushing a jet of water in one direction. That's a point source. A gyre-style unit works differently. Instead of a narrow jet, it uses a wide, thin impeller housed in a long chamber to move a broad sheet of water across the tank, more like a river current than a fire hose.

Point-source pumps vs gyre flow

A standard propeller pump moves a lot of water through a small cross-section. That creates strong localised current with dead zones everywhere else, unless you run several pumps and fight them against each other to build turbulence. It works, but it's uneven, and detritus still settles in the corners the jets can't reach.

A gyre unit spreads the same volume of water across a much wider intake and outlet, so the flow is gentler in peak velocity but far more even across the tank's width. Instead of one strong current and three quiet corners, you get one broad current moving the whole water column, edge to edge.

Why SPS-dominant tanks benefit

Acropora, Montipora and other small-polyp stony corals evolved on reef flats and slopes where surge and current move in wide, sweeping directions, not narrow jets. Laminar gyre flow mimics that better than a single powerhead ever will. Polyps extend fully on all sides of a colony rather than just the side facing the pump, which means more even tissue growth and fewer shaded, slow-growing patches on the back of frags.

The wide flow also keeps fine detritus and uneaten food in suspension long enough to reach a filter sock or skimmer intake, rather than settling into rockwork crevices where it breaks down and feeds nuisance algae. Tanks running a single gyre unit alongside a return pump often need less manual siphoning of sandbeds and low-flow zones.

Sizing by tank litres

The Gyre 300 series, with its reinforced magnet mount, is built for glass and acrylic in the small-to-medium reef range. As a rough guide:

• Under 200 litres: one Gyre 300 unit mounted mid-height usually provides enough turnover without blasting frags directly.
• 200 to 450 litres: two units, one at each end of the tank running in opposition or alternating, gives a genuine cross-tank current without a strong dead zone in the middle.
• Over 450 litres: most keepers pair gyre flow with a larger return manifold or additional propeller pumps for peak turnover, using the gyre unit mainly for even laminar coverage rather than total volume.

Match total system turnover to bioload and coral mix rather than chasing a single number. A lightly stocked LPS tank can run less flow than a densely packed Acropora system.

Placement tips

Mount the unit so its outlet runs parallel to the front glass, roughly a third of the way down from the surface, so the current sweeps across the aquascape rather than straight down into the sand. Avoid pointing it directly at delicate branching frags on the first day; ease new pumps in on a lower duty cycle if you're running it through a controller, then increase output over a week or two once corals show they're handling it. Pairing the pump with a controller from our apex range lets you build slow pulsing or random reef-crest patterns instead of one flat, constant push.

A note from the shop floor

We swapped a customer's twin 6000L/h propeller pumps for a single Gyre 300 last year on a 300 litre mixed SPS tank in Wynnum, purely because his Acropora were bleaching on the shaded side away from the jets. Three weeks later he sent photos of even polyp extension on all faces of the same colonies, and his filter sock was catching noticeably more fine detritus each week, proof the gyre was actually lifting material off the rock instead of just rearranging dead spots. That's the real test of laminar flow: does the whole tank move, or just the bit facing the pump. Gyre-style flow, sizing and stock levels shift, so check out our stock list for wavemakers before planning your next flow upgrade, and browse our marine-aquariums range if you're speccing flow for a whole new build.