Borates in pool

Why should one use Borates

Adding borates can improve your experience with your pool, but is completely optional. If you do plan to use borates, wait until everything else is settled down before adding borates, especially TA and PH. The only situations where we specifically recommend using borates are for pools with a negative edge or other very large water feature creating huge amounts of aeration and for spas using the dichlor and then bleach method. All that said, borates have proven popular with a fair number of people.

Benefits of using Borates

• More stable PH
• Helps prevent scaling in a SWG cell
• Silky water feel
• More sparkle

Downfalls of Borates

• Additional expense
• Concerns about risks to pets
• Not a magical potion to solve all pool woes

How to add Borates to your Pool

We recommend maintaining borates between 30 and 50 ppm. That normally means raising the borate level to around 50 each spring, so that it will still be above 30 come fall.

Before you start on borates, adjust your TA level toward the low end of the appropriate range for your pool type. See the Recommended Levels chart for appropriate levels. It is easier, and better, to adjust TA before adding borates than it will be after.

There are two approaches to adding borates to the pool: boric acid, or a combination of Borax and muriatic acid. Using boric acid is just slightly more expensive, in most cases, and much easier. Borax and muriatic acid takes more effort and handling that much acid is just slightly risky, but saves just a little money (if you shop carefully).

Boric Acid

Boric acid can be purchased from DudaDiesel and The Chemistry Store. Granular is much easier to work with than powdered. Technical grade is fine.

Distribute the boric acid across the surface of the pool. Keep the pump running for at least one hour after adding boric acid, and then test the PH and adjust if needed.

Boric acid will just slightly lower the PH. Usually the PH change is small enough that no further adjustment is required.

Borax and Muriatic Acid

Borax and muriatic acid can be found at grocery stores and hardware stores respectively. Make sure you double check the strength of the muriatic acid, using half strength acid when you thought it was full strength can lead to problems with PH.

When adding to the pool, you add one gallon of 31.45% muriatic acid, followed by 3 1/2 boxes of Borax, use PoolMath to verify the amount and double check the weight on the box. (For pools smaller than 10,000 gallons it is better to add a half gallon of acid followed by about 1 3/4 boxes of borax each time.) Acid should be poured slowly in front of a return jet with the pump running. Borax can be pre-dissolved in a bucket and then poured slowly in front of a return.

That process is then repeated until you have added the correct total amounts to the pool. The final dose will, of course, be smaller. If you see any undissolved borax, brush the entire pool to help mix it in and get it to dissolve.

24 hours later, test the PH and adjust as needed.

Testing Borates

None of the available borate tests are especially precise. Fortunately, the exact level is not critical and just needs to be in the 30 to 50 ppm range. We recommend using LaMotte Insta-Test Borate Test Strips. They aren't great, but they seem to be the best available choice that isn't wildly expensive.

A mannitol test for borates has been developed by some creative members. It is a bit complex and you can read about it here.