PEP Tech

Backyard Pools Still Busy in Fall

The Pool Season is Still On

Normally, back to school and Fall sports lead to an end of the pool season. By September activity shifts away from the backyard and to the classroom and the field. This year due to Covid-19, that shift may not materialize in the same way. Many schools may have delayed openings or not open and there will be more online learning. Also, many sports programs such as football and soccer are being postponed or cancelled for the season. This means there will still be plenty of activity in the backyard pool. After a long, hot and busy summer this can put an increasing strain on the pool.

Seasonal Testing Still Needs to Be Done

Fall is a good time to catch up and do seasonal maintenance and testing. This is the time to test for cyanuric acid CYA, phosphates, total hardness and total dissolved solids TDS. Based on results, Fall is a good time to perform draining and dilution of the pool as well. Summer is hard on pool water. Increased swimmers, heat, long hours of sunlight, extra chemicals and the high evaporation rate all lead to poor water quality and high chlorine demand. A CYA level of 100 ppm means it will take a daily maintenance level of 7.5 ppm of chlorine to destroy bacteria and keep algae from growing in the pool. Simply stated it will require more chlorine to achieve the same affect, this costs more money! A TDS level that is 1500 ppm over source water means it will take 50% more chlorine to keep the pool clean and clear. High total hardness leads to scale and damage to heaters and pool surfaces. Therefore, it is important to conduct seasonal tests along with draining and dilution to bring the water quality back. With pools still in use this Fall it will be vital to talk to your customers and schedule time ahead to do the extra work required for revitalizing the pool.

How Much to Drain Based on Test

There is a simple method for determining how much water to drain to bring water quality back to acceptable levels. For example, if the total hardness of the pool shows 600 ppm and you want to bring it back to 350 ppm use the following formula:

  • Simply subtract the 350 ppm from the 600 ppm and that gives you 250 pp
  • Then determine the total hardness of the source water from the tap. For our example we will say the tap total hardness is 150 ppm. Now you subtract 150 ppm from 600 ppm and that gives you 450 ppm.
  • Take the two numbers and divide them to determine how much of the pool should be drained to get to 350 ppm total hardness. 250/450 ppm = 55%

Draining and dilution is one of the most effective ways to bring water back to recovery after a long busy summer. This year the challenge will be working it in while the backyards are still busy with pool users. One of the best ways to bring the chlorine level back after a drain and dilute is with liquid sodium hypochlorite (chlorine). 1 gallon in 10,000 gallons will act fast to clear and clean the water. Liquid is ideal because it will not contribute any additional CYA or calcium to the pool.

Terry Arko, HASA Inc.