Understanding the effects natural disasters can have on pools

In Canada, the evaporation rate is higher in southern areas than it is in the north. A Government of Canada evaporation rate study, conducted between 1957 and 1966, found the evaporation rate to be the highest in regions such as southwest Saskatchewan and southeast Alberta where approximately 900 mm (35 in.) of water was lost from lakes and ponds annually. For pools in these regions, increased evaporation means the buildup of solids in the water will also increase, leading to higher TDS, calcium hardness, and pH. As a result, more acid is needed to maintain proper water balance during these drier, hotter days.

Also, as TDS increases, the effectiveness of chlorine (Cl) is reduced. In fact, a TDS that is 1500 parts per million (ppm) over the start-up water can lead to a 50 per cent reduction in the effectiveness of chlorine as a sanitizer. Unfortunately, if a region has declared an extreme drought, then draining of pools can be restricted. If the pool cannot be drained and diluted to lower the TDS, 50 per cent more chlorine will need to be added to the water just to keep a residual of free available chlorine (FAC).

Proactively reducing organic contaminants through weekly shocking and the use of a natural-based polymer clarifier can help to slowdown the buildup of these solids. Also, since phosphates are a part of TDS, using a weekly phosphate removal product can help keep levels lower.

Lower water levels

Another problem during drought periods is groundwater gets used up more quickly. Groundwater is what comes from rain that permeates through the soil and then makes its way below ground through cracks and fissures. As groundwater levels get lower, more contaminants are found in the source water which can lead to higher total hardness, minerals, and metals.

According to the National Groundwater Association (NGWA), almost half of the U.S. population gets its drinking water from groundwater. The concentration of metals, such as copper (Cu) and iron (Fe) increase in deep groundwater. Stain and scale inhibitors, as well as metal sequestering treatments, will need to be used, particularly in areas using well water.

Further, as groundwater levels drop, chloride levels increase from an influx of brackish water. This leads to more particulate and higher dissolved solids. The use of shock treatments and natural polymers to floc and remove these to the filter can help. Nitrates can also be a big problem in groundwater, which can have a direct affect on FAC in pool water. Nitrates create chlorine demand which devour FAC levels. Heavy shocking may in these cases, but draining and using trucked in water, which is free of nitrates, would be the best solution.