Fi-Clor Spa Hardness Increaser is used to raise the calcium hardness level in spa water. Calcium hardness is the amount of dissolved calcium and magnesium in pool water. If there is insufficient dissolved calcium, it will be difficult to balance the water - there could also be grout loss in tiled spas.
High levels are not a major cause for concern provided the pH and alkalinity are within recommended parameters, but the reading should be kept below 750mg/l (ppm) if possible.
The dose rate is 10g Fi-Clor Spa Hardness Increaser per 1,000 litres (220 galls) of spa water. Each dose will raise the hardness by approx 10mg/l (ppm).