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August 9, 2016

Myths and Facts:  Water Chemistry

Myths and Facts:  Water Chemistry

Taking care of a pool comes down to science. It really is all about chemistry and physics. For many of us, years removed from high school science classes, it’s not as simple as it should be.  Often, customers come into our store with misconceptions about how to maintain their pool. Sometimes it’s something they learned on the internet, sometimes advice from a neighbour or friend. Whatever the source, if it’s not a solution or system that respects the science of pool care, chances are it won’t work, and in some cases, may cause damage.  Here’s a few “tips” to watch out for:

I don’t bother to balance my pool, I just give it a shot of chlorine every few days and it stays crystal clear!

In fact, you can maintain crystal clear water using just chlorine! A very low pH actually produces very clear water!  If, however, all you do is add sanitizer periodically, you are slowly destroying your pool. Whether too high or too low, too acidic or too basic, your pool water, if not properly balanced, will cause your liner, surfaces, and equipment to age prematurely. Your water can be corrosive to the point that a heater that should last 15 years dies after one season, and no manufacturer will warranty corrosion damage. In addition, improper water balance means the chlorine demand, the amount of sanitizer needed to keep your pool clean and clear, will greatly exceed the quantity needed to maintain a properly balanced pool. Finally, if you are not periodically shocking your pool, you will slowly build up chloramines, the agent that makes your pool and pool users stink.

I have a salt system, my pool is chlorine free and I don’t need to do/add anything but salt!

In fact, a salt system is a chlorinator or chlorine-making machine.  By converting sodium chloride (salt) to sodium hypochlorite (liquid chlorine) a salt system offers convenience, but absolutely does not make your pool chlorine free.  Salt systems also have a hard time in many pools raising the chlorine level fast enough to adequately shock the pool, so, for example, after a big rainstorm, many salt pools require treatment with old-fashioned shock.  Salt systems cannot operate in water below 70 degrees, meaning a salt pool needs to be maintained using old-fashioned chemicals in spring and fall.  Finally and very importantly, all of the same issues exist with respect to water balance; a salt system does not eliminate the need to monitor and adjust pH, alkalinity, hardness, etc…  In fact, a salt pool tends to drive pH up, creating a demand for regular adjustment (lowering) of the pH.

I leave an automatic cleaner in my pool all the time so I don’t need to vacuum it or do other maintenance!

A good automatic cleaner, especially many of the new “smart” robotic cleaners, is a huge help when it comes to keeping your pool clean. Even the best cleaner will miss one or two spots, for example pool steps, so it is always a good idea to periodically brush or manually vacuum the pool to clean those areas. No automatic cleaner is designed to give the pool the scrubbing it needs if you get surface algae. If you do get an algae bloom, you are far better off to use a manual brush. Finally, it is never a good idea to leave any cleaner in your pool “permanently.” Pool water is a harsh environment, and most cleaners are best used once or twice a week then removed. With suction-side cleaners, using them constantly is hard on the pump and the pool surface, and can wear out the liner. Plus, they impede the normal operation of your pool skimmer. Periodic use is great, constant use is ill advised.

I backwash for two minutes once a week no matter what!

Believe it or not your sand filter actually works BETTER when it is a little bit dirty.  A layer of fine debris settling on or on your sand makes the filter more efficient at trapping small particulate. If you clean your filter too often, not only are you wasting water (and the chemicals used to balance and treat the water), you are also limiting the filter’s ability to manage fine debris. Use the 7 pound rule; after a good, long backwash, check the filter pressure. This reading is your “clean” pressure. Do not backwash until the filter pressure increases by 7 pounds. Remember that every pool is different based on the pump size, pipe length and type, distance from the pool, etc.., so your “clean” pressure might be 20 pounds, and your neighbors’ might be 10 pounds. Also it is better to backwash a pool less often but for a longer duration, 3 to 5 minutes. Check the discharge water and keep backwashing until it runs clear!

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