How many return inlets do I need?

Two to four for typical family pools — roughly one per 15 m² of surface, spaced to keep the whole basin rotating.

Are main drains required?

Requirements vary by country, but a drain (or floor suction point) is always worth it: it circulates deep water and makes emptying possible.

Why does my pool have an algae corner?

That corner sits outside the circulation loop. Re-aim your inlets to push water through it, or add an inlet nearby.

Pool circulation: skimmers, inlets and drains explained

Clean water isn't made by the filter alone — it's made by water actually reaching the filter. That's circulation.

5 min read

The loop: out, clean, back

Every pool runs one loop: water leaves through skimmers (or the overflow channel) and the main drain, passes the pump and filter, and returns through inlets. Good circulation means every corner of the pool joins that loop a few times a day; bad circulation means dead zones where algae start.

Surface out: skimmers or gutter

Dust, pollen, leaves and sunscreen float — so the surface needs constant harvesting. Skimmer pools use wall units, one per ~25 m² of surface, placed downwind on the wall facing the prevailing breeze. Deck-level pools skim their entire perimeter through the overflow channel, which is why their water looks so polished.

Deep out: the main drain

A floor drain at the deep point pulls from the bottom, where heavy debris and cold water settle. It also makes draining and winter maintenance practical. Modern drains are anti-vortex covered and pair with safety standards — in the designer you'll find one placed at the deep point by default.

Back in: return inlets

Return inlets push filtered water back, angled to set up a slow rotation across the pool. Wall inlets suit skimmer pools — placed opposite the skimmers so water sweeps the surface toward them. Deck-level pools often feed from floor inlets instead, pushing clean water up through the whole depth; that's why our designer lets returns be wall- or floor-mounted.

Frequently asked questions

How many return inlets do I need?: Two to four for typical family pools — roughly one per 15 m² of surface, spaced to keep the whole basin rotating.
Are main drains required?: Requirements vary by country, but a drain (or floor suction point) is always worth it: it circulates deep water and makes emptying possible.
Why does my pool have an algae corner?: That corner sits outside the circulation loop. Re-aim your inlets to push water through it, or add an inlet nearby.