How do I test my Spa Pool for Alkalinity?

One of the most important water parameters to keep balanced is ‘Total Alkalinity’, the water’s capacity to resist acidification. But what does that mean exactly and what impact does it have when it’s out of balance?

What is Total Spa Pool Alkalinity?

Often referred to as ‘TA’, total alkalinity describes how well your water will cope with sudden changes to the water pH level. You see, pH works as TA’s bodyguard in many senses. Your water’s pH level can be drastically thrown out of whack by small little contaminants, however, when you have your Total Alkalinity set correctly, this will absorb the hit, before the contaminant has an effect on your pH. Total Alkalinity is measured in parts per million (PPM). You want to aim for a reading on your test strip between 80-120ppm.

Note: pH is the measurement of how basic or acidic a substance is, and it’s measured on a scale of 0-14. Your ideal spa pool water pH reading is between 7.2 and 7.6. See the Article here for more detail on pH.

How do I test for Total Alkalinity?

When Total Alkalinity is out of balance, your pH likely will be too, and therefore is susceptible to fluctuation, resulting in discoloured cloudy water and potentially scaly buildup. Without these parameters being within their correct ranges, the effectiveness of your sanitiser is also considerably reduced.

To start, you will simply pick a test strip out of your bottle, and dip it into the centre of the spa water, before holding it there for approximately ten seconds. Following that, you will pull the test strip out of the water, flick off any residual droplets and wait 30 seconds to see your results. You will now be able to compare these results to the key provided on the back of the test strip bottle, just like our example above. You want to see a test strip color reading that’s somewhere between 80ppm – 120ppm – outlined by the OK range. If your Alkalinity is out of line, check your pH level too, as when one is out, often the other is too.

How to fix a low Total Alkalinity Reading

You might find a fresh fill of water has a slightly low TA reading and needs to be raised. In this circumstance, you want to reach for your pH Buffer (iluka elevate) as adding this will bring your TA up. This product is designed to boost your water’s TA without having a big impact on your pH level.

However, if you find your water’s pH level has risen too high after this process, that can be easily fixed. Adding pH Decrease (iluka descend) will bring that pH level back down, without affecting your TA too much. See page 21 of our Spa Pool Water Care Handbook for dosing charts.

How to fix a high Alkalinity Reading

High Alkalinity is a relatively uncommon issue for spa pool users who are following our guideline of draining and refilling their spa every three months. The main cause comes from adding too much pH Buffer when trying to deal with low pH. While the pH buffer will raise pH levels slightly, Total Alkalinity will be raised more dramatically, so it’s best to get some pH Increase (sold separately) if you’re wanting to raise pH levels often, as pH increase has little effect on Alkalinity. See page 22 of our Spa Pool Water Care Handbook for dosing charts.

Which do you Adjust First? pH or Alkalinity?

It always depends on what your test strips are currently telling you but generally, you want to get Alkalinity set within range first, before moving onto pH. Ensure you always conduct a new test before adding any chemicals.

If both pH and alkalinity are low, start by increasing your alkalinity. Following that, retest your water, if you find the pH is still low, but the alkalinity is good, simply add some pH increaser.

Tips for Keeping Alkalinity Balanced

Change your spa water. At least every three months and then rebalance.

After adding chemicals to your spa pool, allow 15 minutes for your water to circulate before retesting.

Balancing your alkalinity between 80-120PPM will help to lock pH within the 7.2 – 7.8 ideal range. Ensuring your alkalinity is correctly set when you first start up your spa, will make it much easier to balance going forward.

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