FreshWater pH/Alkalinity Down is a fast-dissolving granular product that lowers both the pH and total alkalinity of your spa water. Active ingredient: sodium bisulfate, a dry acid that's much safer to store and handle than liquid muriatic acid while doing the same chemistry job. Works with every common sanitizer program — chlorine, bromine, ozone, biguanide, FreshWater Salt, Hot Spring ACE, and Ag+ Silver Ion. High pH and high alkalinity sound like the safer direction to err — but they're just as damaging as the low side. When pH climbs above 7.8, three things go wrong at once: chlorine becomes drastically less effective (at pH 8.0, chlorine is roughly half as active as at pH 7.5), scale starts forming on heaters, jets, and salt cells, and cloudy water becomes the new normal regardless of how much chemistry you add. Sodium bisulfate brings water back into the healthy 7.2–7.8 range so the rest of your sanitizer program can actually do its job. The proper target ranges, recommended by Watkins Wellness: pH: 7.2–7.8 Total Alkalinity: 80–120 ppm One bottle handles dozens of corrections for a typical residential spa. This is the natural sibling product to FreshWater pH/Alkalinity Up — together they cover the full range of acid/base adjustments most owners ever need. Pro Tip: Owners of FreshWater Salt System or Hot Spring ACE spas typically use pH/Alkalinity Down more often than Up. Salt-generated chlorine is mildly alkaline as a byproduct of the electrolysis process, so pH naturally drifts upward over time. If your salt-system pH keeps creeping above 7.8 between drain-and-refills, this is the product that brings it back into range. Brand FreshWater®
