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.
Clearly, when cyanuric acid is in the water, it overpowers pH in terms of controlling chlorine strength.
CYA is acidic and it keeps on lowering PH the entire time it is dissolving. Metal Free is also somewhat acidic. Sequestrant slowly decays in the pool. That is why regular maintenance doses are required.
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.
If you need the pH level in the pool to rise, you need to add pool conditioner or stabilizer directly to the pool.
To raise the pH levels in your pool, try adding sodium carbonate (soda ash) or sodium bicarbonate (baking soda) until your pool's pH levels are between 7.2 and 7.8.
Cyanuric acid, also called stabilizer, is commonly used in outdoor pools to reduce photodecomposition of available chlorine. When added to pool water, a fraction of the cyanuric acid (H3Cy) ionizes to form cyanurate (H2Cy-). The fraction that ionizes is pH-dependent.
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.
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.
While shocking and adding algaecide is effective in getting rid of algae, it should not be done together. This is because when you mix chlorine and algaecide together, it renders both of them useless. Hence, you should first shock the pool and wait for the chlorine levels to fall below 5 PPM.
Why You Have Low Cyanuric Acid
The most likely reason is that you've only ever used unstabilized chlorine in your pool. Heads up: Unstabilized chlorine, such as sodium hypochlorite (liquid chlorine), lithium hypochlorite, and calcium hypochlorite, is pure chlorine.
Baking soda is the best way to raise total alkalinity with minimal effect to pH and cyanuric acid.
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.
What happens when CYA in a pool is too high? – CYA Levels exceeding a threshold of 70 parts-per-million of cyanuric acid can reduce the effectiveness of the chlorine in a pool. The amount of time it takes to kill bacteria lengthens as the concentration of CYA increases.
Areas exposed to high levels of sunlight should maintain 60 – 80 ppm (parts per million). Pools using an ORP Controller (Oxidation Reduction Potential) such as the AutoPilot Total Control, should maintain 30-50 ppm. Indoor pools do not need cyanuric acid, unless it gets periodic exposure to sunlight.
Obtaining a pH level requires an aqueous solution because pH is the result of the comparative amount of free hydrogen and hydroxyl ions in a water-based solution. Adding baking soda with its pH of 9 to water with a neutral pH of 7 raises the pH level of water.
Alkalinity is the total alkaline material in your pool water. You should test alkalinity first because it will buffer pH. Your reading should be in the range of 80 to 120 parts per million (ppm).
If your pH is high and alkalinity is low in the same water, you may need to add pH reducer/minus and then alkalinity increaser to your pool to lower pH and increase alkalinity respectively. In very rare cases, your total alkalinity may be high but with a low pH in the same pool.
Adding a basic substance such as sodium carbonate will increase the pH. With proper care, your pool will stay at an ideal pH level of 7.2-7.6, which makes your chlorine up to ten times more effective. It will also prevent any sort of maintenance issues or irritation and redness for bathers.
Proper pool pH is right in the middle — pool pros recommend that pH be between 7.3 and 7.6 for optimum performance and cleanest water. If the pH gets higher than 7.8, the water is becoming too alkaline.
High chlorine levels decrease the pH of your pool's water, making it more acidic. The more acidic the water, the higher the likelihood of corrosion. This corrosion can affect metal piping, equipment, and the surface of your pool (tiles, liners, concrete, etc.).
Acid, on the other hand, lowers both pH and total alkalinity.
Most pool experts recommend a pool pH between 7.2 and 7.8. To raise or lower pH, a pool custodian simply adds acids or alkalis into the water. For example, adding sodium carbonate (soda ash) or sodium bicarbonate (baking soda) will generally raise the pH, and adding muriatic acid or sodium bisulfate will lower the pH.
Pool Pro Hydrochloric Acid (also referred to as HCL) is used for lowering pH in Pool Water. Test pH weekly. The recommended range is between 7.2 and 7.6. If the pH is higher than 7.6, correct it by adding the Hydrochloric Acid as shown on the following table.