Pool Crystals, Plaster Dust, and other Calcium Issues in Pools | Orenda Whiteboard
Are you sure you're looking at scale?
https://blog.orendatech.com/opening-a...
Especially in colder climates, people often mistake underwater calcium crystals for scale. In reality, carbonate scale is the opposite problem. https://blog.orendatech.com/calcium-c...
According to the LSI, scale is formed when the water is over-saturated with calcium. Calcium carbonate falls out of solution and lands on surfaces like tile lines and spillways. Again, looking at the LSI, this explains why scale is most often found where the sun is warmest...like dark tile with good sunlight. Why? because warm temperature increases the LSI. Think about your shower head or faucets at home. When scale forms on them, it's because the water is so hot it creates an LSI violation. Heaters and salt chlorine generators scale before the pool does for the same reasons...within them, the LSI is higher.
Cold water is corrosive: https://blog.orendatech.com/pool-wint...
The opposite is true too. The colder the water, the lower the LSI, and therefore, it's more corrosive. Crystals that form underwater usually occur during the winter because the water is cold, and the pool is woefully low on the LSI. It means the water is out of balance, and needs more calcium! So what does it do? It tries to take calcium from anywhere it can...like the plaster surface.
Calcium is the most misunderstood chemistry in the pool business: https://blog.orendatech.com/calcium-m...
When conditions are right, calcium hydroxide bleeds out of the surface and reacts into some other form of calcium that can form crystals. Those crystals are often mistaken for scale. And they're not. We had them laboratory tested. At least three types that we have tested are a form of calcite (a dense, skeletal growth of calcium carbonate) which the lab believes "grew out from the plaster". They are not deposits from the water.
We also know of other types of crystals like calcium sulfate, calcium phosphate, and calcium silica.
An example of this is using acid-based products to remove these crystals. Acid further lowers the LSI. And while you get instant results (acid reacts with calcium quickly), the problem will come back after you leave. It drives pool managers crazy...but it's because the problem was diagnosed incorrectly. Both of the problems, however, can be treated with LSI balanced water and a non-acid-based chelant like Orenda SC-1000.