Bob Lowry Explains Why Borates Matter

Borates have a long history in professional pool care, but they’re still widely misunderstood. Pool pros often hear that adding borates is a “set it and forget it” upgrade, yet the chemistry doesn’t work that way. Borates can improve swimming pool water chemistry by helping slow pH rise and supporting algae prevention, but they do not replace proper sanitation or balanced water. If your free chlorine is low, your cyanuric acid (CYA) is off target, or your LSI is out of range, borates will not rescue the pool. The real value is stability and predictability, not a magic fix.

A key takeaway is that chlorine and CYA rules still apply even with borates in the water. The conversation stresses keeping free chlorine at roughly 5% of CYA, with a hard minimum of about 2 ppm, instead of trying to “cheat” with very low CYA and tiny chlorine targets. Low CYA can also expose the limits of testing accuracy and leave chlorine unprotected in sunlight. For many outdoor pools, 20 to 30 ppm CYA is a practical minimum, and higher chlorine targets require proportionally higher CYA so the sanitizer holds. Borates help, but only after the basics are right.

Borates also change the day to day pH story in a way many people don’t expect. Yes, borates act as a pH buffer, so pH tends to rise more slowly, which is especially helpful in saltwater chlorine generator pools where aeration and the cell can push pH upward. The tradeoff is simple: once pH does climb, it can take close to twice as much muriatic acid to bring pH back down compared to a pool without borates. That is why it’s smart to dial in target pH and total alkalinity first, then add borates, instead of adding borates on top of already high pH and alkalinity.

Product choice matters as much as the target level. The episode draws a sharp line between boric acid and borax based products such as sodium tetraborate decahydrate. Boric acid is favored because it has minimal impact on pH and only slightly reduces total alkalinity, making it easier to add without causing turbulence in water balance. By contrast, borax based additions can drive pH very high and significantly raise total alkalinity, forcing large acid corrections. If a pool already has high pH, high alkalinity, and high calcium hardness, that swing can push LSI positive and trigger calcium precipitation, leading to cloudy water.

So what borate level should you target? Many pros land on 50 ppm borates as the effective, practical level for pH stability and algae suppression support, with some field reports pushing to around 70 ppm for saltwater pools. The discussion also touches on EPA related limits and why some packaged products label lower recommendations for legal or regulatory comfort. Testing is still a hurdle: options include borate test strips and instruments like the LaMotte Spin Touch, but many techs rely on careful dosing math based on pool gallons and the amount added. The good news is borates do not evaporate, so they usually only drop with water loss from backwashing, splash out, leaks, or drain and refill, making seasonal top offs far more common than full re-doses.