Automation and pH Control for Your Pool

In Blog, Chemistry, Controllers by Timothy Petsch

I have just visited with a high end HOA, in the desert, close to Las Vegas to discuss upgrading their water to a Salt Pure® system. As is my habit I began my site visit with a tour of the mechanical room and a discussion on current pool operations.

Keep in mind that this is a high end residential development, with all the amenities that one could ask for, including 2 outdoor pools and a large spa.

Their method of operation was to have a pool service company come by twice a week in the winter months and 3 times in the summer to vacuum the pool, backwash the filters (whether they needed it or not!), presumably take water chemistry readings and then dump, yes dump, liquid chlorine and acid into the water. I asked the folks if they ever saw algae in the pools and if their skins ever itched, and if they had water quality issues…there was a resounding YES to all three!

No chemistry controller, no client oversight, heaters had failed, and the pools needed to be replastered.

My first recommendation was that they automate before switching systems. Why? Well, what they were not aware of is the vitally important role the pH plays in recreational water. The chlorine the service company was using, Sodium Hypochlorite has a pH of around 12.9, pool water needs to be 7.2-7.6 (we prefer 7.4). So as soon as the chlorine is introduced to the water the pH spikes up; these guys knew that so they chased it with a healthy dose of Acid to lower the pH, and then job done they left the site. Did the pH stay in the lower acceptable range? No, it did not…after it bottomed out it began to climb back up, and as it got into higher range the chlorine became less and less effective resulting in lower quality and potentially unsafe water.

Automating your pH, from the author’s point of view is the most critical step you can implement in a commercial pool. pH cannot be controlled! It is constantly fluctuating and when manually adjusted, fluctuations can be extreme. Automation constantly monitors the pH in the water, using a sensor, and injects small amounts of acid as needed, continuously, tightening the pH bandwidth.

In short, if you are manually adjusting your chemicals in your commercial pool, and do only one thing to improve your water quality and safety, that one thing should be automating your pH.