Methods of combat
Two water treatment methods can help counter the effects of rising pH in salt pools: scale inhibitors and pH decreasers.
Over time, scale accumulates on the cell plates as a result of the cell’s high scaling conditions. As accumulation proliferates, also known as fouling, the electric current passing between the ECG plates for chlorine production is impeded and eventually comes to a halt. To help combat this phenomenon, most ECG’s have a reverse polarity function, which changes the direction of the electric current within the cell, purging accumulated scale from the plates.
Further, cell acid cleaning can also alleviate the inevitable stunted chlorine production of the cell. However, like a favourite T-shirt that gets washed over and over, leaving behind a tattered rag, the cell will eventually lose its protective coating with more and more acid cleanings leading to equipment failure. To maintain the longevity of the cell, the best practice would be to use a treatment which prevents scale accumulation from forming on the cell plates altogether—right? Wrong. Although this seems like the practical answer to maintaining a long-lasting ECG, unfortunately, it is not that simple. Even with reverse polarity functionality and acid cleanings, over time ECG plates will accumulate scale regardless of the treatment used. Scale inhibitors can be used, however, to slowdown the process of cell fouling.
In doing this, the frequency of abrasive cell acid cleaning can be reduced, thus improving the cell’s lifespan. Different scale inhibitors will have varied functionality and stability in salt pool environments. Polymer-based scale inhibitors typically provide a useful blend of performance and stability within the harsh environment of an ECG.
Sodium hydroxide production is one of the reasons why the ECG environment is so harsh. While operating, the ECG essentially produces pH increaser leading to constant pH rise in salt pools. Depending on pump runtime and the chlorine output settings, the ECG will gradually push the pH up. Therefore, like any other pool, salt pools require the pH to be monitored and adjusted for proper balance. Basic water balancing steps can be taken to fight pH rise in salt pools with the principal agent of treatment being sodium bisulfate (NaHSO4)-based pH decreaser. Sodium bisulfate not only decreases pH, but since it is a granular product, it is also much easier to handle than liquid pH decreasers. Checking pH balance weekly, and after heavy-cell usage, will help establish when and how much pH decreaser should be applied.
For most salt pools, weekly applications of pH decreaser are going to be the best way to counter pH rise. There are numerous benefits to maintaining proper pH: chlorine is going to be more effective at killing bacteria; bathers will be more comfortable; and pool surfaces and equipment such as heaters and ECG’s will be better protected against scale accumulation. Maintaining the cell and chlorine output through use of stabilizer, scale inhibitors, pH decreasers, and supplemental oxidation extends the life of valuable pool equipment, including the ECG.