Does high cyanuric acid affect pH?

Author: Prof. Blaze Harvey DDS  |  Last update: Friday, May 20, 2022

All alkaline materials are buffers. Cyanuric acid happens to be the most common buffer found in pool water. In effect, cyanuric acid helps stabilize both chlorine and pH. It binds with chlorine to prevent photolysis and it keeps pH elevated.

Does cyanuric acid affect pH?

Clearly, when cyanuric acid is in the water, it overpowers pH in terms of controlling chlorine strength.

Does CYA decrease pH?

CYA is acidic and it keeps on lowering PH the entire time it is dissolving. Metal Free is also somewhat acidic.

What happens when cyanuric acid is too high?

When cyanuric acid levels get too high, it can cause something referred to as chlorine lock, which basically means your chlorine has been rendered useless. You'll know it has happened when your chlorine test shows very or little chlorine even right after you've added it to the pool.

Does high CYA affect alkalinity?

When cyanuric acid is added to the pool, it increases the total alkalinity, but not the carbonate alkalinity, which is the alkalinity that matters in water balance.

The Problem with High Cyanuric Acid (CYA) with Chemistry Expert Bob Lowry

Does cyanuric acid raise pH in pool?

All alkaline materials are buffers. Cyanuric acid happens to be the most common buffer found in pool water. In effect, cyanuric acid helps stabilize both chlorine and pH. It binds with chlorine to prevent photolysis and it keeps pH elevated.

Is it safe to swim in a pool with high cyanuric acid?

Although there are no known adverse health effects associated with high CYA concentrations, most health officials usually limit CYA levels to 100 ppm. Some states recommend a lower level for spas, and some jurisdictions ban the use of CYA altogether.

How do you reduce cyanuric acid in a pool?

Yes, the most economical way to lower CYA is to partially drain and dilute the pool with fresh water. Consult a pool professional if you want to drain more than 1/3 of your water, because there are risks with hydrostatic pressure and other concerns.

Why is my cyanuric acid high in my hot tub?

The most common way hot tubs increase cyanuric acid is by adding stable chlorine to their hot tub (e.g. dichlor or trichlor). These chlorine solutions include stabilizer in them, which means cyanuric acid is added every time chlorine is added.

Do salt water pools need cyanuric acid?

Cyanuric Acid in a Saltwater Pool

Hayward and Pentair both recommend 60-80 ppm of cyanuric acid for their salt systems. Why more CYA? Manufacturers of salt systems want more output from the salt cell, without fighting against UV degradation. As cyanuric acid bonds to chlorine, the chlorine residual can build faster.

Will pool stabilizer raise pH?

If you need the pH level in the pool to rise, you need to add pool conditioner or stabilizer directly to the pool. As usual, follow the directions because some manufacturers may have you dilute the powder in a bucket while others suggest that you sprinkle it directly on the pool surface.

What should my pool pH be?

A pH level of 7 means that water is neutral; above 7 means the water is alkaline, while below 7 indicates acidity. Aim for a pH level of between 7 and 7.6. If the water pH is higher than 8, anyone who swims in the pool is at risk of skin rashes, while a pH of lower than 7 can sting swimmers' eyes.

What raises cyanuric acid in a pool?

Cyanuric acid is raised by adding chlorine stabilizer containing cyanuric acid. The only way to lower cyanuric acid is by replacing water.

What causes low pool pH?

The most common cause of a consistently low pH level in pools is using chlorine tablets or stabilized forms of chlorine. These have a pH level of around 3. Acidic rainfall, heavy leaf debris, and dirt/mulch in the pool can also lower the pH level.

What should my cyanuric acid be?

Saltwater pool manufacturers recommend keeping your cyanuric acid levels between 60 and 80 ppm. Remember, more cyanuric acid does not mean more protection from the sun. If your CYA levels are high, you may experience algae growth or cloudy pool water. That's because your chlorine's effectiveness is reduced.

How do I lower the cyanuric acid in my pool without draining it?

In fact, cyanuric acid has been known to stay in pools even after completely draining them – it can get into the plaster. The only way to lower the levels is to drain some water and add water with no CYA in it.

Does CYA affect bromine?

Note: Since cyanuric acid stabilizer doesn't work with bromine, there is no need for a CYA test in kits that only contain a bromine sanitizer test, such as Taylor's Complete™ FAS-DPD kit (K-2106).

Does CYA reduce over time?

Yes, entirely possible. As you point out, there is a testing variance to consider and CYA will naturally degrade a few ppm per month, maybe a little more.

Does cyanuric acid float or sink?

We also found that cyanuric acid is denser than water so it sinks to the bottom of a body of water.

Does cyanuric acid dissipate over time?

The problem is that cyanuric acid does not dissipate or evaporate but instead lingers and gathers in the pool water. Over time, the pool technician would be required to constantly re-apply Tri-Chlor or Di-Chlor products to re-sanitize the pool.

Does tap water contain cyanuric acid?

Cyanuric acid is present in drinking water when chemicals commonly referred to as dichlor (anhydrous sodium dichloroisocyanurate or sodium dichloroisocyanurate dihydrate) or trichlor (trichloroisocyanuric acid) are used as alternative free chlorine sources.

Can high cyanuric acid cause cloudy water?

Remember that cyanuric acid is very strong, and if it exceeds the recommended levels, free chlorine will disappear, and the water will turn cloudy and be at high risk of algae growth. In summary, if your combined chlorine reads above 0.5 ppm, your water may turn cloudy and become unsafe for swimming.

Does muriatic acid effect cyanuric acid?

Does Muriatic Acid Affect Cyanuric Acid? Both muriatic acid and cyanuric acid can be used in your pool with minimal adverse effects on each other. Although, as with any chemical, it's best not to dump a whole lot into your pool at the one time or mix chemicals.

How much cyanuric acid should be in a pool?

You should keep your outdoor pool or spa's Cyanuric Acid level at 0-30 parts per million (PPM).

Is muriatic acid the same as cyanuric acid?

Cyanuric acid technically is an 'acid' but is dissimilar to muriatic acid, which the pool industry uses to manage and adjust pool pH levels. It is sold as a standalone product or can be purchased as a convenient additive to chlorine tablets.

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