Underwater View of a Swimming Pool

Why is my pool water “hard” and why does it get “harder”?

From the day your pool is first filled, it is often above the standards for pool water chemistry in Calcium Hardness (200 to 400 parts per million, or ppm) and continues to increase as you remove water by getting out of the pool, splashing or evaporation. To replenish this lost water, new water is added and additional hard water is introduced; raising the concentration levels of this hard water (predominantly Calcium and Magnesium) and creating a higher level of these minerals. This level increases, creating such hard water that your chemicals can no longer do their job, dictating the need for higher chemical levels to keep the pool safe. Additionally, scale builds on your interior finish, tile, pool plumbing and equipment, which can lead to failure and expensive repairs!

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How is hard water typically addressed?

In the past, the water was dumped down the drain! If the average pool has 20,000 gallons of water and if only 1,000 pool owners (out of the tens of thousands in our area!) dump their water a year, that means 20,000,000 gallons of water is not only wasted, an additional 20,000,000 is needed to refill these pools! Using the very realistic recovery of water with our system (80%), that would mean an annual savings of 32,000,000 gallons of water a year!

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Are there chemicals that I could use to address this water hardness?

While there are products that will hold the hardness minerals in suspension, they will not lower the level of hardness. This is a short term approach and a costly one as well, as you are not only paying for these chemicals, but are also changing the chemistry of the water and requiring higher sanitizer levels to maintain a clean, safe pool; you are only prolonging the inevitable! The only true way to bring your Calcium Hardness to ideal levels is to filter your water and bring the levels down to the acceptable range. This means lowering your Calcium Hardness closer to the 200 PPM range, which is the low end of the ideal range.

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I can’t see the hardness in my pool; how do you know it’s really there?

You may not be able to see it in the water (although we suggest turning your lights on one night and see if you see anything floating around in your pool!), but you can see and feel the effects in other areas. Maybe you have a raised spa wall with a spillway; do you see the ugly white residue on it? Perhaps you’ve noticed that the waterline tile doesn’t look quite so clean any longer. How does your hair feel when you get out of the pool… maybe like straw? Or do you feel like you have to run for the skin lotion after swimming because you feel dry and itchy? Hmmm, maybe you have noticed this without even realizing it!

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What other problems could occur with hard water?

Did you know that heat creates Calcium Carbonate? This is a very hard mineral deposit and it can-and does-affect your heater. Once this Calcium Carbonate builds up in the heat exchanger, the heater cannot efficiently heat the water, and it takes longer and consumes more gas than it should. Over time, the heat exchanger will fail and the heater becomes useless. New heaters are very expensive!

A Calcium buildup in your pool pump will eventually cause your pump to fail as well. Did you know that swimming pool pump manufacturers do not warranty pumps (or heaters, for that matter) that have failed due to hard water deposits? Pumps, while not to the extent of heaters, are also very expensive to replace.

How about that algae that you can’t seem to get rid of? For pool chemicals to work properly, they have to be able to assimilate into the water. If they cannot get through the hard water easily, they cannot attack the algae.

Does your plaster look like it has a disease? That is scale or hard water build up, and it is not only unsightly, but also detrimental to the plaster itself. Once your Calcium Hardness levels get high enough, the calcium builds on itself and the blotchy “stains” appear. Some may even look like small stalagmites growing up and out of your pool floor and walls! This scale can also deposit itself in your pool plumbing lines and inside your filter.

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