Increasing your pH

The pH of your pool can affect your skin and eyes as well as kill the power of your chlorine or make your pool murky.

What are the effects of low pH?

  • Low pH irritates the skin and eyes. It can also irritate the mucous membranes in your nasal cavity. This is because acidic water will strip away your body’s natural oils.
  • Low pH corrodes equipment. Everything in contact with acidic water is basically being worn away, which is why if left unchecked, it will corrode your plumbing, accessories, liners and other equipment.
  • Unbalanced pH kills chlorine’s power. Whether it’s low or high, unbalanced pH is the super-villain of your pool’s germ-fighting hero. In this scenario, you can add all the chlorine you want and your pH levels will render it useless.
  • High pH clouds the water. While cloudy water in and of itself is not necessarily unsafe, it does usually signal an underlying issue. And besides, no one wants to swim in murky water!

What do I do if I have to increase my pH?

If your pH is too low PoolSense will be asking you to add pH Up in order to increase your pH. Whilst pH Up is a brand, you can use a number of products to do the same thing. Unfortunately, the chemical consequence of adding a product like BoraxpH Up or Soda Ash is that your pool can go milky or cloudy. It’s not dangerous and will clear up. In this article, we try to explain what is happening and why it’s happening and offer suggestions around the best way to minimise this effect.

Soda Ash

How does Soda Ash work?

Soda Ash is an additive to raise the pH and alkalinity in swimming pools. Soda Ash has a high pH, somewhere between 11.3-11.7. Those of you reading this who have used Soda Ash may have had it cloud up your pool.

Most pool owners have a limited understanding of chemistry but for some, it is important so for those technically minded pool owners – what is the chemistry behind this? To raise the pH of water Soda Ash works by stealing hydrogen atoms to become bicarbonate, the reaction looks like this:

Na2CO3 + H+ ↔ 2Na+ + HCO3

Soda Ash + Hydrogen yields Sodium and Bicarbonate

This all ties into the broader discussion about alkalinity and pH. We know in the pool business that alkalinity is a pH buffer, but do we know why? In a less-than-scientific explanation,  alkalinity buffers pH by either donating a Hydrogen atom or absorbing one. In other words, Alkalinity makes it more difficult for pH to fluctuate quickly. When you add Soda Ash to the pool, the carbonate anion (CO32-) wants to become bicarbonate (HCO3-). To do so, it needs to get a Hydrogen (H+) from somewhere. When carbonate takes its Hydrogen atom, the pH goes up. This pH and alkalinity chemistry is about equilibrium, so the opposite is also true. When you add acid to the pool, a Hydrogen is released and the pH goes down. That’s the science, practically let’s talk about why it sometimes clouds up a pool.

Rapid pH Change can cause cloudiness

When you add Soda Ash to your pool the extremely high pH can create a high-LSI violation in its immediate vicinity. This explains why the cloudiness does not happen all at once, rather the process creates a cloudy plume that slowly expands across the pool. This cloudiness is just calcium carbonate or plaster dust coming out of solution. If you simply let your pool filter it will eventually clear.

How to Use Soda Ash in your Pool

Don’t add more than 500grams of Soda Ash for every 20000litres. Keep your pump running for 24 hours and add over the surface of the pool starting in the deep end. Wait for the next PoolSense reading and see what happens. Repeat the process if necessary.


Using Borax to increase your pH

An alternative to Soda Ash is Borax, it will not make your pool go cloudy like Soda Ash. But how exactly does Borax in pool help with your pool’s pH balance, and how should you do it?

What Does Borax Do For a Pool?

Borax is a type of salt or chemically derived from boric acid, used in many cleaning recipes. Some say it’s a safer alternative to using soda ash, and it can easily be found in your local grocery store at an affordable price. An added benefit to using Borax in your pool would be that it prevents algae growth and makes your water sparkling and soft.

How to Use Borax in Pool

When attempting to raise your pool’s pH levels by adding Borax in the pool, here are the things you’ll need:

  • pH testing kit (PoolSense)
  • Borax
  • Safety gloves

Borax use – 4 Steps

It’s very easy to use Borax in your pool, just follow these steps:

Step 1 pH Test

Test your pool water for its acidity level. The ideal range would be between 7.4 to 7.6. If lower, then you will need to raise the pH level with Borax.

Step 2 Measure Borax

Measure about 500grams of Borax for every 20,000 litres of water in your pool. This should raise the pH level by up to 0.5.

This will all depend on the chemical content of your water, so make sure to underestimate, as it’s better to have lower pH levels to easily adjust.

Step 3 Add Borax

Switch on your pool’s water pump to let the Borax circulate. Then, add in Borax to the deepest part of the pool, letting the pump run for three days.

Step 4 Check pH Levels

After three days, check the pH levels as reported by your PoolSense monitor to see if it is within the ideal range. If still too low, then add in more Borax, using the same measurements as last time (or less, depending on the pH level).

Take note that if the pH level is higher than the ideal range by about 0.2 or less, then there’s no need to worry. It will naturally decrease after a few weeks.


Orenda Technologies – Eric Knight
Doityourself.com – How to raise Swimming Pool pH – Heather Corman


PoolSchool Effects of Low pH

PoolSchool ORP vs PPM

PoolSchool – Pool Chemistry