Reef Matcher

The question behind every reef build is "what does my tank actually need?" Enter your tank volume, the corals you keep and your bioload, and the Reef Matcher returns your required total turnover (GPH and ×/hr), the skimmer rating band to shop for, a return-pump target, a PAR range for your reef, heater wattage, ATO reservoir sizing and a welfare-conscious fish-stocking ceiling. The numbers do the arguing so you stop guessing. Parameter-based and sourced to established reef rules — not prescriptive husbandry, and not a substitute for testing your own water.

Your tank's total water volume in US gallons. (Rough rule: length × width × height in inches ÷ 231.)

Sets your turnover and PAR targets — SPS want the most flow and light, softies the least.

Drives how much skimmer headroom you need and your stocking ceiling.

How this is calculated
  • Turnover (×/hr) by coral type. Soft corals/most LPS sit around 10–20× turnover, mixed reefs around 20–30×, and SPS around 30–50× delivered as random turbulent flow. The matcher uses the middle of each band as the target × and multiplies by your gallons to get total GPH.
  • Return pump vs total flow. A return pump typically supplies a modest share of total flow (a common target is ~5–10× turnover through the return, accounting for head-loss), with powerheads/wavemakers making up the rest. The matcher splits the total accordingly.
  • Skimmer rating band. Skimmer box ratings are optimistic, so the matcher sizes a skimmer rated above your display volume — more headroom for a heavier bioload. Light bioload ≈ 1.5× display gallons, medium ≈ 2×, heavy ≈ 2.5×, shown as a band.
  • PAR target. General coral-group ranges measured at the coral: soft ~50–120, LPS ~100–200, SPS ~200–350, mixed ~100–250. Acclimate corals up to higher light slowly.
  • Heater wattage. The common rule of thumb is ~3–5 watts per gallon depending on room temperature and tank size. The matcher uses ~4 W/gal and, on larger tanks, suggests splitting it across two heaters for redundancy.
  • ATO sizing. Reefs evaporate roughly 1–2% of volume per day. The reservoir recommendation covers about a week of top-off so salinity stays steady between refills.
  • Fish stocking ceiling. A deliberately conservative, welfare-conscious guide based on display volume — fewer, well-chosen fish keep a reef stable. This is a ceiling to stay under, not a target to fill.

These are rules-of-thumb derived from established reef references and manufacturer rating conventions — not bench measurements of named products, and not a prescription for your specific tank or livestock. Always test your own water and follow each product's instructions. This is general reef-keeping information, not veterinary advice.

Once you have your numbers, the buyer guides match the gear to them. Start with the best protein skimmers for the rating band above, then the best wavemakers and powerheads for your turnover and the best reef tank heaters for the wattage.

Affiliate note: our guides earn from qualifying Amazon purchases at no cost to you. Full disclosure. Specs are verified against manufacturer details and current listings — no hands-on testing claims. Livestock guidance is general reef-keeping information, not veterinary advice.