Why it’s important to get your pools Calcium level well balanced

Getting your pools Calcium level right is not as daunting a task as it may seem, however it is important! The ideal Calcium range for most pools is between 200 and 400ppm.


First. Lets consider??your Calcium balance from a simplified perspective. Really, when it comes to Calcium, there are only 3 possible scenarios.

  1. Your pools water is under-saturated (Calcium levels are low);
  2. Your pool water is saturated (Calcium levels are just right); and
  3. Your pool water is over-saturated (Calcium levels are too high).

Water (and any solution) will always try to find it’s “balance”. That is to say that if it is under-saturated, it will attempt to draw whatever minerals it is low in from whatever it comes in to contact with, mainly the pools surface itself and this is what makes your pool water corrosive. Vice versa, if your pool water is over-saturated, it will result in scale deposits, usually around the pools water line and in equipment, this is simply chemicals within the water that cannot dissolve as the water has already met its demand for that particular chemical.

A Simple Experiment
If you are finding this information hard to grasp. I propose a simple experiment. Go and fill a glass with water, grab some salt from your kitchen and a spoon to stir with. Start adding salt to the water a little bit at a time and stir. What you will find is that the water will absorb the salt. BUT! A point will come at which the water will be completely saturated with salt and the salt will no longer dissolve. When this point is reached, the salt will simply fall to the bottom of the glass as a deposit. This is over-saturation.

Deposits on a tiled pool due to high Calcium

The reason it is so important to maintain your Calcium level is because concrete and plaster pools in particular contain Calcium. If, as explained above, your calcium levels are low, the water will begin to corrode the pool surface by extracting calcium from it. Concrete pools in particular can eventually begin to crater, creating voids that algae loves to find its way in to and spread. Conversely, fibreglass pools for example do not contain Calcium in the pool shell, and so it is not overly important to maintain Calcium balance in the water, however it is always a good idea.

If you find that your Calcium level is low, increasing it is easy. Give me a call! Or, go to your local pool shop, confirm your current Calcium concentration, buy a Calcium product and add it evenly over the surface of the water to the required quantity.

If you find that your Calcium level is high, decreasing it is also easy, though can take a little more care and time. There are product that can be bought that are designed to reduce Calcium, however are often expensive and I recommend getting a professional to do this. The easier way is to drain some of your pool water out, and refil. If you do opt to drain and refil your pool, be sure to check that you haven’t upset the balance of other chemicals too much in the process.

If you have any questions regarding keeping your Calcium balanced, please contact me.

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