Work out exactly how much soda ash, calcium chloride or magnesium to dose from your tank's real water volume, and how many days to spread the correction over so it doesn't cost you coral tissue.
The calculators
Alkalinity calculator: How much soda ash or sodium bicarbonate raises your alkalinity by a given dKH, from your tank's real water volume, and how many days to spread the correction over.
Calcium calculator: Work out how much calcium chloride raises your reef tank's calcium to target, from real water volume rather than the number on the box, with the safe daily rate built in.
Magnesium calculator: How much magnesium chloride or sulphate your reef tank needs to reach target, from real water volume. Worth checking before you chase alkalinity or calcium that will not hold.
Salt mix calculator: How much salt mix to weigh out for a given volume of RODI water at your target salinity, and what a water change actually costs you per month.
Tank volume calculator: Work out your reef tank's actual water volume from its dimensions, minus rock and sand, so every dose you calculate from it is right rather than roughly right.