A rough hard layer has formed on the acrylic. What is this and what can I do about it?

It is a lime precipitate. SpaBalancer alters the lime molecules. It strives to precipitate excess lime. Therefore, lime precipitation may occur in hard water containing lime. This manifests itself in a whitish to brownish coating on the shell of the spa. This coating can be sandy or floury. Most of the time it is very easy to wipe off with a brush. Sometimes it sits a little more firmly on the surface. In contrast to a normal lime precipitation, without SpaBalancer, this lime layer does not form a stone-like continuous shell. Thus, the lime is also not harmful to the technology of the spa.

If the coating is very difficult to remove, then I recommend lowering the pH to 5.5 for one to two days. This acidic water softens the lime. It can then be wiped off very easily or disappears by itself. After wiping necessarily filter the water thoroughly so that the suspended particles are removed from the water.

Normally, you have this lime precipitation only once when refilling the spa. It can occur diminished also again if water is refilled. If the water is very hard, lime precipitation can occur several times. Whenever SpaBalancer is added to the water, this lime precipitation occurs. It stops when the water is soft enough. You can speed up this process by increasing the dosage slightly in the beginning and lowering it again as soon as the lime precipitation stops.

To minimize this lime precipitation, it is recommended to lower the pH, which is usually very high in the beginning, to 7.0 to 7.4 in the first four to six weeks. Later, the pH will automatically level off at around 7.0.