Important limitation: The KH/pH formula assumes carbonate buffering is the primary influence on pH. Active soil, peat, acids, buffers, tannins and other compounds can make the result inaccurate. Never increase CO₂ based on a calculator alone; watch livestock closely and maintain strong circulation and oxygenation.

This is a dilution estimate. It assumes water is completely mixed between changes and nitrate production does not continue during the calculation period.

Always follow the salt manufacturer’s mixing instructions. Add salt to circulating purified water—not water to a pile of dry salt—and verify the finished batch with a properly calibrated salinity instrument before use.

Salinity changes should generally be made gradually in occupied aquariums. This calculator uses ppt because specific-gravity conversion depends on temperature and instrument calibration. Match replacement-water temperature and verify each step with a calibrated refractometer or conductivity meter.

Prime tubing and eliminate air bubbles before calibration. Use the same tubing length, head height, container and fluid the pump will use in normal operation. Recalibrate after tubing, pump-head or fluid changes.

Heater, chiller and variable-speed pump consumption changes with room temperature, settings and workload. Enter the estimated average-load percentage rather than assuming the nameplate wattage runs continuously.