Calculator
Reef Flow Calculator
"More flow" is reef advice; a number is a plan. Your target depends on what you keep — softies sway, SPS demand a storm — and your return pump is already doing part of the job. Enter both and get the real gap, plus the wavemakers that close it, ranked by what they cost to get there.
Return flow is what the pump delivers after head loss, not the box rating — the return pump calculator computes it →
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Where the targets come from
The 20–40× total-turnover baseline is Bulk Reef Supply's published guidance — softie/LPS tanks at the lower end, SPS at the top. We band it: softies/LPS at 20–30×, mixed reefs at 25–40×, and SPS at 40–60×, because surveys of standout SPS tanks consistently run above the textbook minimum (one survey of 20 such tanks averaged 85×). Wavemaker flow numbers below are manufacturer max ratings, priced and sourced on 2026-07-11.
Placement beats horsepower
Two moderate pumps on opposite ends, aimed to collide, produce the chaotic flow corals want; one monster pump produces a laminar river and a sandstorm in front of it. That's why the results below quote pairs where a single unit falls short — and why "one giant unit" is rarely the right buy even when the math allows it.
The budget-tier trade, stated plainly
Budget pumps (Jebao and kin) genuinely move the rated water at a quarter of the premium price — the trade is service life (owners consistently report 1–2 years) and a heavier cleaning schedule. That can still be the right call for a first tank; it's just a real trade, not a free lunch, and we label it instead of hiding it.
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