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.
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.
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.
Dilute your pool water if the levels are above 80 ppm.
The easiest way to lower the levels of cyanuric acid in your pool is to simply dilute the water. Partially drain your swimming pool by the same percentage by which you want to reduce your cyanuric levels.
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.
And stabilized chlorine (like dichlor or trichlor) already comes with CYA, so you'll likely be adding it to your pool water throughout the season. Because CYA is an acid, you'll need to handle it carefully. It can damage your filter and your pool, especially if you have a vinyl liner.
Adding Cyanuric Acid reduces the sun's impact on chlorine loss. The longer chlorine is present in pool water, the longer it's available to kill bacteria and sanitize the water. In the pool industry, Cyanuric Acid is known as chlorine stabilizer or pool conditioner.
For cyanuric acid:
Acute toxicity: Cyanuric acid (syn: isocyanuric acid) is of low toxic in acute toxicity studies. This chemical is considered to be slightly irritating to eyes, but not to the skin.
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.
Saltwater pool manufacturers recommend maintaining cyanuric acid levels around 60-80 ppm. This is a bit higher than the 30-50 ppm range recommended for non-saltwater pools. And if you live in an area where your pool gets a lot of direct sunlight, you may even consider bumping your cyanuric acid up to 80-100 ppm.
Regular bleach, or sodium hypochlorite – contains no cyanuric acid. Household bleach is normally a 5% or 6% strength, while commercial strength bleach for pools is generally 12.5% strength, and delivered by truck and hose.
Sometimes called "isocyanurates" or "CYA," cyanuric acid is used to condition or stabilize a pool's chlorine. Cyanuric acid has chemical reactions with free chlorine molecules to protect it from UV light and degradation from the sun.
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.
You should keep your outdoor pool or spa's Cyanuric Acid level at 0-30 parts per million (PPM).
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.
Cyanuric acid is raised by adding chlorine stabilizer containing cyanuric acid. The only way to lower cyanuric acid is by replacing water.
The time it takes for cyanuric acid to dissolve is 2 to 5 days. What is this? It's important to be patient during this time and wait for it to fully dissolve before adding more cyanuric acid to the water. Cyanuric acid levels will continue to increase until all of the chlorine stabilizer has completely dissolved.
Answer: Cyanuric acid shouldn't be at Zero for an outdoor swimming pool because chlorine will deplete faster in hot and humid weather, leading to cloudy water. If your FC is at normal level of 3ppm, raise Cyanuric acid level to 40 ppm and you will reduce chloramine levels that make your water appear cloudy.
As applied in water, the chlorine and cyanuric acid mixture (Tri-Chlor or Di-Chlor products) would eventually break down and the chlorine would dissipate away as usual. The problem is that cyanuric acid does not dissipate or evaporate but instead lingers and gathers in the pool water.
1) No, unfortunately CYA doesn't go down with evaporation. You will need to drain/replace some water.
Clorox has absolutely NO Cyanuric Acid (CYA) in it nor does it increase CYA at all when you use it. You should show them. It's mostly water, then sodium hypochlorite (i.e. chlorine), and sodium chloride salt, and then a small amount of sodium hydroxide and a very small amount of sodium polyacrylate.
Cyanuric acid (CYA), also called stabilizer or conditioner, is used in pools and spas exposed to the sun to reduce the rate of decomposition of available chlorine by ultraviolet rays in sunlight. Stabilized forms of chlorine, such as dichlor and trichlor, contain CYA in their formulas.
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.