What to expect when the weather goes from dry to wet
Every service professional knows the importance of keeping pool water balanced; however, what might not be known is the importance of adjusting water balance prior to the first rainfall of the season.
Acid rain is a phenomenon many have heard about as a result of pollution in the atmosphere. During dry seasons, there can be a buildup of nitrogen (N) and sulphur (S) compounds in the air. When the moisture from rain or fog combines with these compounds, the result is nitric and sulphuric acid (H2SO4).
When acid rain enters pool water it will have an immediate effect in lowering the pH. This explains why many times after the first heavy rainfall of the season service professionals report a drop in pH in many of the pools they maintain.
To prevent this from happening, service professionals should make sure the TA levels in the pool water are correct before the rain begins (TA is the buffer to resist pH changes). By making sure the pool water’s TA levels are in the 80 to 120 ppm range, it can help prevent the pH from dropping when acid rain hits.
What is in rain?
Despite what some 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. Therefore, any rain that falls into the pool is carrying organic and inorganic substances, bacteria, and nitrogenous compounds of minerals and metals.
Further, after it rains, it is typical for algae to become a problem in pools. This is because rain can increase nitrate levels, which are a known food source for algae. Also, due to the impurities in rainwater, chlorine demand can become much greater and sanitizer levels can be reduced to zero. Therefore, after a heavy downpour, it is important to test for nitrates, super-chlorinate the water, and use an all-purpose algaecide.
| Water maintenance guidelines for pools that are under the weather |
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| • During a drought, the saturation of water increases due to low groundwater levels and higher rates of evaporation. • Pool water draining restrictions during times of drought can lead to an increased use of chemicals to maintain sanitary water conditions. • Evaporation is one of the leading causes of pool water loss when it is warm and dry. • Solid or liquid covers pool can help reduce evaporation. • Water sources can change rapidly during times of drought; therfore source water should be tested regularly. • The first rainfall of the season can introduce a number of contaminants to the pool which will have an affect on the water chemistry. • The acid content of rain can be higher during the first rainfall and can have a direct affect on pH. • Manage alkalinity levels prior to heavy storms. • Flood waters can introduce various contaminants to the pool, including raw sewage that can contain bacteria and Cryptosporidium. • Phosphate levels can increase after a heavy wildfire season due to ash and the use of fire retardant chemicals. • Proactive shocking, phosphate removal, clarifier, and algaecide use can help in all-weather scenarios. |
Great read – thank you Terrry