I have filled my whirlpool with a Spa Pure filter for soft water. Do I still have to add Calcium Ex?
The idea of the Spa Pure filters is to soften the water when filling the whirlpool. The filters contain ion exchange resins in spherical form, which contain sodium ions. When the water flows through the ion exchange resins, the sodium ions are dissolved from the water. A calcium ion from the water is placed in the place of the sodium ion. This softens the water.
There are three problems with this system.
1) The water flows very fast through the ion exchange resins. This means that only a small part of the ions can be exchanged.
2) These filling filters contain a maximum of 200 g of granulate.
Here is a calculation of the ion exchange capacity:
- Water hardness Water pipe: 20 ° German hardness
- Water hardness to be achieved in the whirlpool tub: 7 ° German hardness
- Water volume in the whirlpool tub: 1,000 litres
- Required quantity of granulate: 1.5 kg
It is obvious that the filling filters are not capable of softening the water sufficiently.
3) The ion exchanger granules consist of resin. This resin contains a certain amount of moisture. They must not be allowed to dry out under any circumstances, as this would cause cracks to form in the beads. Through these cracks, the resin in powder form gets into the water. This can lead to brown deposits. Unfortunately, the filling filters are not completely airtight and nobody knows how old they are when you buy them. So there is a possibility that you buy a filling filter in which the resin has already dried.
We recommend our Calc Down Pads for water softening. These pads are always produced fresh by us in small quantities and stored in a sealable PVC bag so that they cannot dry out.
So you still need to add Calcium Ex.