Bob Lowry Explains Why Borates Are a Game-Changer

Borates have become one of the most practical “set it and forget it” upgrades in modern pool chemistry, especially for pool service pros managing a weekly route. The big appeal is simple: borates are typically a one-time addition that you only verify occasionally, yet they deliver ongoing benefits in swimming pool maintenance. At the recommended borate level of about 50 ppm, they act as a secondary pH buffer that helps slow the upward pH drift many pools experience. That matters most in saltwater chlorine generator pools, and in pools with constant aeration like spillovers, waterfalls, negative edge designs, or heavy return turbulence, where carbon dioxide outgassing pushes pH higher and higher.

The second benefit is algae prevention. Borates are best described as an algostat rather than an algaecide: they do not “kill” algae the way chlorine does, but they can make it harder for algae to get started. That distinction is important for realistic expectations and for sanitation. You still need a proper free chlorine level, balanced cyanuric acid, and circulation and filtration. What borates can do is buy you time and stability, especially when temperatures rise and bather load increases. Some pros also report a noticeable “sparkle” or clarity shift after adding borates, a visual improvement that can help with customer satisfaction even if it’s difficult to measure in a lab.

Product choice matters because it affects how much correction you do after dosing. Boric acid is often preferred because it dissolves easily and has minimal impact on overall balance, typically nudging pH down slightly and lowering total alkalinity only a small amount. By contrast, sodium tetraborate products such as borax can drive pH up significantly and raise alkalinity, which then forces you to add muriatic acid to bring water balance back to target. Chemically, once dissolved and in the water, the resulting borate species provides the same ongoing effect, but the “getting there” step can be smoother with boric acid. If you cannot find pool-specific borate products, some pros source boric acid through landscape or nursery suppliers, while borax is widely available in grocery and big-box laundry aisles.

Questions about safety and legality come up often, so it helps to keep the conversation grounded in math and local code. ppm is a tiny unit, and at 50 ppm the borate concentration is low relative to the total water volume, which is why it is used as a supplemental buffer rather than a primary sanitizer. Toxicity concerns are frequently overstated; the key points discussed include dose, body size, and the fact that borates do not bioaccumulate in mammals. On regulation, residential pools usually have fewer restrictions, while commercial pools may depend on state and local health codes, NSF requirements, and specific product approvals. The practical takeaway for pool pros is to treat borates as a stability tool: use them to reduce pH swings, support algae resistance, and deliver more consistent water for your clients.