Aqua-Semidol is produced from pure dolomite. It is composed of 23 – 28% MgO and 72 – 77% CaCO₃. It is successfully used to raise the pH of water by binding carbon dioxide (CO₂) and adding calcium and magnesium to the water.

Aqua-Semidol will dissolve (1.2 – 1.3 gram per gram CO₂) and needs to be replenished from time to time. The filter media is to be used in continuous flow systems only, to prevent possible cementing of the filter bed.

In systems where the flow is too low, the pH will be overcorrected.