01
Maintenance
Water-change volume
Turn a percentage into the amount of new saltwater to prepare.
Prepare approximately4.88 gal18.5 liters
Use actual system water volume when known, not only the manufacturer’s display-volume label.
Friendly answers for everyday reef keeping
Free reef aquarium calculators
Three small tools for the calculations reef keepers repeat. Results are estimates, so confirm equipment and husbandry decisions against manufacturer guidance and your actual system.
02
Planning
Rectangular tank volume
Estimate gross and displaced water volume from inside dimensions.
Gross volume34.3 gal
After displacement29.2 gal
Not suitable for curved, bowfront, or irregular tanks without a geometry adjustment.
03
Running cost
Equipment electricity cost
Estimate the monthly energy and cost of a pump, light, heater, or other device.
Monthly energy87.7 kWh
Estimated cost$14.03
Nameplate wattage and actual draw may differ. Heater and chiller duty cycles also vary with room conditions.
Keep the results organized