Calculators

Reef tank calculators that open into the planner

Each tool uses ReefCrafter sizing rules, shows the math, then sends the same gallons, goal, bioload, and tier into the build planner.

Skimmer size

Protein skimmer size calculator

For most reefs, size the skimmer to 1.5x display gallons for light bioload, 2x for medium, and 2.5x for heavy.

target rating = display gallons x bioload factor
Heater wattage

Reef tank heater wattage calculator

Plan reef heating inside the 2.5-5 watts per gallon band, then split heat across two heaters on tanks 50g and up.

2.5 <= total watts / display gallons <= 5.0
Flow target

Reef tank flow calculator

Soft and LPS reefs often start around 10-20x turnover, mixed reefs around 20-40x, and SPS systems around 40-60x.

target display flow = display gallons x reef-goal turnover
Return pump GPH

Return pump GPH calculator

Most sumped reef systems want roughly 5-10x system turnover delivered after head loss.

rated pump GPH = target delivered GPH / head-loss factor
Lighting coverage

Reef lighting coverage calculator

A reef light has to cover the tank footprint and hit the PAR band for the coral goal.

fixture coverage >= length x width and PAR >= coral target
Cost estimate

Reef tank cost calculator

A real reef budget includes the startup cart, first-90-day supplies, consumables, and a margin for fixes.

real budget = startup cart + first-90-day supplies + repair cushion
Build check

Reef build checker

The safest pre-buy check is cross-category: tank, goal, bioload, light, flow, heat, filtration, and water all have to agree.

build passes when every required category clears its rule threshold

Want the full cross-check?

The calculators are fast single decisions. The planner combines the same numbers across equipment, budget, and livestock so one good choice does not hide another weak spot.