What is Calcium Hardness?

Calcium Hardness is the amount of dissolved calcium in the pool water. The test for Calcium Hardness is a measure of how hard or soft the water is when it’s tested.

Hard water can have high levels of calcium and magnesium. If these levels are too high, the water becomes saturated and will throw off excess particles out of solution that then seek to deposit on almost any surface inside the pool. This is calcium carbonate scale: a “white-ish,” crystallized rough spot.

If the levels are too low, the water is under-saturated, and the water will become aggressive as it attempts to obtain the calcium it needs and will tend to dissolve calcium out of plaster, pebble, tile, stone, and concrete.

Problems Indicating Low Calcium Hardness:

  • Pitting and etching of the plaster
  • Dissolved grout in your pool
  • Staining of the pool surface
  • Possible heater failure
  • Corrosive and scaling water
  • Supersaturation
  • Swimming pool stains

Problems Indicating High Calcium Hardness:

  • Skin and eye irritation
  • Cloudy swimming pool water
  • Clogged pool filters
  • Poor filtration
  • Calcium build-up and corrosion on heaters
  • Scaling of the pool water

With a little practice and regular attention, you'll become more confident in your ability to maintain proper chemical balance. Until then, we're always here to help you keep everything on track. Having problems balancing and maintaining your pool water? NO PROBLEM! Bring your water sample into one of our stores & let our chemical experts test it for FREE!

Have a chemical question? Your pool is our business, so don't be shy!