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FreshWater pH/Alkalinity Down

SKU: 80041
$11.39

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Description

FreshWater pH/Alkalinity Down

Overview

FreshWater pH/Alkalinity Down lowers pH and total alkalinity in hot tub water using sodium bisulfate — a granular dry acid that's safer to handle than liquid muriatic acid and dosed precisely for spa-sized water volumes. Add it when your test strips show pH above 7.8 or alkalinity above 120 ppm to bring water chemistry back into the safe zone where sanitizer works correctly and your skin stays comfortable.

Why this matters more than most owners realize: High pH (above 7.8) is one of the most common — and most expensive — water chemistry problems in hot tubs. Chlorine becomes up to 50% less effective above pH 7.8. Calcium scale precipitates onto heaters and salt cells. Cloudy water becomes the new normal. Sodium bisulfate fixes all three in a single dose.

What Sodium Bisulfate Does

Sodium bisulfate (NaHSO₄) is a granular dry acid that releases hydrogen ions into spa water as it dissolves — neutralizing alkalinity and lowering pH back into the ideal range. Unlike liquid muriatic acid (which is more aggressive and dangerous to handle), sodium bisulfate is solid, easier to measure, and safer to store.

One product, two readings improved: each dose lowers both pH and total alkalinity at the same time. For most owners with high readings, this is the only adjustment chemical they need.

What’s in the Box

  • 1 × FreshWater pH/Alkalinity Down — granular sodium bisulfate
  • Dosing instructions printed on the label

Key Features

  • Sodium bisulfate (dry acid) — safer to handle than liquid muriatic acid
  • Lowers both pH and alkalinity — one product solves the most common high-reading problems
  • Granular, fast-dissolving — works through the filter system in minutes
  • Compatible with all sanitizer systems — chlorine, bromine, ozone, biguanide, FreshWater Salt System, and ACE Salt System
  • Safe for every spa surface — won't damage acrylic shells, jets, pillows, or covers when added to the filter compartment
  • OEM Watkins Wellness formula — manufactured to spa-grade purity standards

Directions

  1. Test your water with FreshWater 5-Way Test Strips to confirm pH is above 7.8 and/or alkalinity is above 120 ppm.
  2. Calculate the dose: Add 1.5 oz per 500 gallons of spa water for a standard adjustment. For a typical 350-gallon residential spa, that's about 1 oz per dose.
  3. Turn on your circulation system and run jets to mix the water.
  4. Pre-dissolve in a bucket of water if your spa has a vinyl interior or sensitive jets (acrylic shells can take direct dosing into the filter compartment).
  5. Add the granules to the filter compartment with the jets running — never sprinkle directly into the spa where they may settle on jets, pillows, or the spa shell.
  6. Wait at least 30 minutes (ideally 3 hours for full equilibration) before retesting.
  7. Retest pH and alkalinity and repeat the process if levels are still above range.
  8. Stop adjusting when you reach alkalinity 80–120 ppm and pH 7.2–7.8.

    Compatibility

    • Compatible with chlorine, bromine, ozone and biguanide sanitizers.

    Brand

    FreshWater®

    Warranty Policy

    Most products purchased from our online shop within the last 30 days are eligible for return. Please review our return policy to see the list of items that cannot be returned.

    Some major items that are non-returnable:

    • Gift cards
    • Electronics
    • Pumps / Motors
    • Hot Tubs
    • Closeouts
    • Fireplaces
    • Electric Fireplaces
    • Massage Chairs
    • See return policy below for full list of non-returnables.