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Drought vs. El Nino

Water Chemistry for a Crazy Climate

By Terry Arko

What to Expect When It Goes From Dry to Wet

Every pool pro knows the importance of keeping pool water balanced. However what might not be known is the importance of adjusting water balance just before the first rain of the season. Acid rain is a phenomenon we have heard about as a result of pollution in our atmosphere. In the dry season there can be a buildup of nitrogen and sulfur compounds in the air. When the moisture from rain or fog combines with these compounds in the atmosphere, the result is nitric and sulfuric acid. When acid rain enters swimming pools it will have an immediate effect on lowering the pH. This explains why many times after the first heavy rain, pool pros report a drop in pH in many of their pools. One thing pool pros can do to prevent a drop in pH from acid rain is to make sure the total alkalinity is correct before the rain begins. Total alkalinity is the buffer to resist changes in the pH in water. Making sure that the total alkalinity is in the 80 to 120 ppm range can help to keep the pH from dropping when acid rain hits.

What's in Rain?

Unlike what we may think, rainwater is not pure. In fact, water is incapable of condensing into droplets without the presence of dust, smoke or other impurities in the atmosphere. A cloud of water droplets can only form in the presence of impurities. So those raindrops that you see splashing on the surface of the swimming pool are bringing with them organic and inorganic substances, bacteria and nitrogenous compounds of minerals and metals. It is very typical after a heavy rain for algae to become a problem in pools. This is because the rain itself can bring an increase in the levels of nitrates, which are a known food source for algae. Also, due to the impurities in rain water, chlorine demand can become much greater and sanitizer levels can be reduced to zero. It is vital after a heavy rain to test for nitrates. Super-chlorinate the pool often following heavy rains and use a good all -purpose algaecide.

The Hidden Dangers of Flood Water

There are several types of flooding that can occur. Flash floods are the result of a break in a levee or dam or heavy rains in mountain areas above a flood plain. This can be very destructive and cause contaminated water to rush quickly and overwhelm low-lying areas. In coastal regions storm surges and high tides can cause flooding. When Hurricane Sandy hit the coast of New Jersey, there were many pool service pros who reported finding live shrimp in their pools after the floodwaters receded. Floodwaters will contain mud, silt, organic materials and very possibly raw sewage that is loaded with bacteria. Whenever floodwaters enter a pool, it is best to drain the pool if possible. If this is not possible, then the pool should be super chlorinated to at least 20 ppm of chlorine at a pH of 7.5. The pool should be kept at 20 ppm for at least 15 hours to ensure that all pathogenic organisms have been inactivated. Also, the use of a natural polymer flocculent can help to clear materials out via the filter. The filter should be thoroughly cleaned once the water has cleared. You may also expect an influx of nitrates and phosphates from floodwaters particularly in agricultural areas or in areas of phosphate mining such as parts of Florida.

Be Ready

There is no denying that weather patterns are changing and in certain areas water itself has become a big challenge. Much of the southwestern United States has seen a drought unlike anything in more than 500 years. Groundwater levels have sunk to catastrophic levels and regulators have imposed strict conservation laws in reaction to this. The building, filling or draining of swimming pools has come under extreme scrutiny from many officials. Despite the fact that it has been proven that pools require less water to maintain than a backyard lawn, they still fall in the crosshairs of lawmakers and private citizens. Pool professionals need to be diligent during these times to ensure that the industry does not become falsely targeted as water-wasters. Having a plan in place on how to conserve and prevent waste of pool water is needed ahead of time. One of the largest water wasters mentioned previously will be evaporation, so if pool pros are diligent and do what they can to reduce the evaporative loss of pool water, that goes a long way in showing pro-conservation efforts. Solid covers can work, and if they are not an option, there are chemical liquid covers that can be applied to reduce water loss from evaporation. When the rains of El Nino begin to move in, it is important to be prepared by making sure all pools are properly balanced. Super-chlorinate after times of heavy rains or flooding. Test the pools for nitrates and phosphates, and be sure to use a good quality algaecide after the rains have past. We can't always predict the weather. But if we are ready for anything then we can prevent the water problems before they begin.

Terry Arko has more than 30 years of experience in the swimming pool and hot tub industry. He has worked in service, repair, retail sales and chemical manufacturing. He has experience in customer service, sales and product development. His expertise is in the area of swimming pool and hot tub water chemistry. Terry is both a Certified Pool Operator (CPO) and CPO course instructor through the National Swimming Pool Foundation (NSPF). He has authored more than 100 published articles on water chemistry. Terry is a popular speaker at many industry trade show events. He authored the "Book on Water Clarity" published in 2005 by Halosource Inc. He currently works with SeaKlear Recreational Water a division of Halosource, Inc. To learn more, visit www.seaklear.com.