How to Raise pH Without Raising Alkalinity (In a Pool)



Trying to figure out how to raise pH without raising alkalinity in your pool?

While the pH of most swimming pools typically drifts upwards over time, if your pH level is too low for comfort, you’ll need to take some extra steps to speed up the process.

We’re going to how to boost your pH with little to no impact on alkalinity, what to do if you accidentally raise your pH too much, and how to keep your pH from dropping in the future.

The Problem With “pH Up” Products

You might be tempted to use one of the many “pH Up” or “pH Increaser” products you see in your local pool store.

What you probably don’t realize, however, is these are basically just common household products with fancy packaging. Specifically, they’ll either be repackaged baking soda, soda ash, or borax.

Here’s why that’s potentially a problem:

  • Baking soda raises pH a little but raises alkalinity a lot.
  • Soda ash raises pH but raises alkalinity.
  • Borax raises pH a lot but raises alkalinity a little.

Since you’re NOT looking to raise total alkalinity, you don’t want to be adding any baking soda or soda ash to your pool.

Borax is a viable option if your alkalinity isn’t already on the high end, but it’s still cheaper to avoid borax-based pool products and just buy standard, off-the-shelf borax. It’s the same substance.

Note: Borax also adds borates to your water. While borates can provide some benefits to pool water, adding too much can be hazardous, especially if you have small pets that regularly drink from the pool.

2 Ways to Raise pH Without Raising Alkalinity

Below are your two best options when it comes to raising pH with little to no impact on your alkalinity.

1. The Aeration Method

Aeration is the easiest, cheapest, and most natural way to lower pH without affecting your total alkalinity.

The process basically involves churning your water for a prolonged period of time and requires no chemicals.

Technical explanation: As you expose more of the water to air, it causes it to lose carbon dioxide at a faster rate (like leaving a soda bottle open). This raises the pH level of the water since dissolved carbon dioxide is acidic.

There are a few ways to aerate your water:

  • Ensure your pool pump running
  • Turn your water features on (deck jets, misters, waterfalls, etc.)
  • Point your jets upwards to break the water’s surface
  • Get people in the people to splash around (throw a pool party?)

You can also to attach to your pool, though these are essentially just another type of water feature.

Finally, if you have a saltwater pool, your saltwater generator is another component that causes a lot of aeration, which is a big part of why saltwater pools tend to have higher pH levels.

This process can take anywhere from half a day to several days depending on your starting pH level, your total alkalinity, and how aggressively you aerate your water.

2. The Borax Method

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Borax has a pH level of 9.5, so adding it to your pool will raise your pH level faster than aeration alone, while minimally raising alkalinity.

It will add borates to your pool, however.

Most pool owners prefer to keep their borates reading below 50 parts per million (ppm) to be on the safe side, though some claim to have it as high as 100 ppm with no reported issues.

Either way, if you have some wiggle room for a small increase in alkalinity, and you’re comfortable increasing borates in your water, this will likely be the preferable method.

Of course, you can also combine water aeration and borax to speed up the process while minimizing the increase in alkalinity and borates being added to the water.

As for how much borax to add, this will depend on your starting pH level, your current total alkalinity, and how much borate is already in your water — so testing your water beforehand is necessary.

Wait, Doesn’t pH Follow Alkalinity?

Yes, pH is influenced by total alkalinity.

In this case, since your total alkalinity is high compared to your pH level, the pH will eventually creep up by itself.

Technical explanation: Higher total alkalinity causes dissolved carbon dioxide to leave your water (off-gas) at a faster rate. Since carbon dioxide is acidic, removing more of it from your water drives up the pH.

But that doesn’t mean you should wait it out. Without help (such as using aeration or borax), this process can be extremely slow and leave your pool in a vulnerable state for far too long.

Not only can acidic water be damaging to your surfaces and equipment, but it also burns through chlorine faster, potentially leaving you unprotected against algae and other contaminants in your pool.

In short, the faster you can get your pH back in range (7.2 to 7.8) without compromising the rest of your water chemistry, the better.

What to Do If You Raise Your pH Too Much

If you overcorrect and raise your pH level too much (over 7.8), you will need to lower it back down.

The problem is, assuming your total alkalinity is still where it needs to be, you now need to lower the pH level without lowering total alkalinitywhich is not realistically possible.

Instead, you’ll need to take a two-step approach:

  1. Lower both pH and alkalinity together using muriatic acid
  2. Raise alkalinity back up using baking soda

We recommend using our chemistry calculator to get more exact measurements for adding muriatic acid and baking soda.

How to Prevent Your Pool pH Falling

Pool water tends to drift upwards in pH level, so if you’re constantly battling against low pH, you have some investigating to do.

The good news is, you probably just have too much acidic substance in your water and there are only so many ways this can happen.

Here’s a checklist you can follow:

  • Switch from chlorine tablets to liquid chlorine.
  • Cover your pool to protect it from rainwater.
  • Test your water source before filling or topping off your pool.
  • Use a mesh cover to keep leaves, twigs, and bugs out of the water.
  • Shower before swimming to wash off sweat, lotions, deodorants, gels, and other toiletry products.
  • Ensure nobody is urinating (or worse) in the pool.

The Bottom Line

There are plenty of options for raising pH in a swimming pool, but not so many if you’re looking to maintain total alkalinity.

Fortunately, the two methods we’ve covered in this article should be all you need to adjust pH in isolation. All it takes is some forced water aeration and a little borax to boot.

Categories: Pool Care, Pool Chemistry