Are 70-80 CYA Levels for SWG Pools Safe?

[sagosto]

In my opinion, 30 to 50 is perfectly fine to use.

If you feel better about that range, that's what you should use. The main thing that we teach is the ratio of fc to cya.

As long as you maintain the ratio according to the fc/cya chart, you should good.

We have found that using a higher cya can be beneficial but I wouldn't have any issues with 40 to 50 cya.

Thanks. It was shocking to see how many resources don’t even mention this. It really helped me. I just did a test

7.5ph
40 cya
130 ta
9 fc

I added a touched of acid and a bit of stablizer. I’ll raise ph if it drops a bit.

 

[mknauss]

I’ll raise ph if it drops a bit.

With that TA, the pH will rise. No need to chemically manage it.

 

[JamesW]

With the TA at 130, I would expect to see the pH trending up. I would not raise it unless it went below 7.2. Try not to micromanage the pH. As long as it's between 7.2 and 7.8, I would tend to leave it alone. Watch the CSI if you have a concrete pool or high calcium hardness.

 

[sagosto]

Apologies as I wasn’t clear. I added acid to lower both but mostly concerned with alkaline. And added touch of cya

 

[IceShadow]

You really don't need to worry about lowering TA levels - high TA levels aren't really going to hurt much except to make the pH raise faster, which means you add more acid, which will naturally over time lower the TA levels.

 

[sagosto]

You really don't need to worry about lowering TA levels - high TA levels aren't really going to hurt much except to make the pH raise faster, which means you add more acid, which will naturally over time lower the TA levels.

I was trying to get to the 70ish mark per what I’ve read on the forums and in the ebook. Not necessary ?

 

[JamesW]

The rule that I use is that if the pH is constantly going too high, the TA is too high.

If the pH is constantly going too low, the TA is too low.

If the pH is stable, the TA is good.

If you have a plaster pool, maintain the CSI between -0.3 and 0.0.

 

[IceShadow]

I was trying to get to the 70ish mark per what I’ve read on the forums and in the ebook. Not necessary ?

Naw. TA is something you need to know because it affects the amount of chemicals you have to add to modify your pH, but you don’t need to try to lower it. It’ll come down as you add acid to lower your pH.

 

[JoyfulNoise]

@sagosto

Have your wife review this -

Assessing the Impact of Cyanuric Acid on Bather’s Risk of Gastrointestinal Illness at Swimming Pools

Current regulatory codes for swimming pool disinfection separately regulate free chlorine (FC) and cyanuric acid (CYA). It is well-known that CYA affects disinfection rates by reversibly binding to FC in aqueous solutions. However, limits for these regulated parameters have neither...

www.mdpi.com

The lead author of this peer-reviewed paper is the same man that helped to develop the chemical levels we use here. The CDC MAHC is currently rethinking its approach to CYA and FC. The problem is that EPA won’t budge on their standards because they don’t really understand the effects of CYA and they are mostly focused on drinking water. The WHO is an international organization that has to harmonize EU concerns (no CYA whatsoever) with US interests. It’s a conflicted set of opinions and I don’t really consider the WHO to be a trusted source. World body organizations rarely care about actual science and are much more politically driven.

 

[AUSpool]

CDC says 15 ppm = https://www.cdc.gov/healthywater/sw...-when-chlorine-stabilizer-is-in-the-water.pdf

As mentioned already, that is the control of cryptosporidium in public pools, is not about the health risks of cyanuric acid (CYA). Its about perspective, how to read all the available information and what does it really mean.

There is a lot of information on CYA, it is a very stable compound. Its final fate, most commonly in a treatment plant, is not reacting as a poisonous substance would, but rather it is eaten as a food source for bacteria.

I wanted to know too, and I’ve run the numbers in the past and just did again. To be at risk a 20kg child would need to drink 950 litres from a pool at 100ppm of CYA. The child would literally drown, die of water poisoning first. (Sorry about the SI units)

The folks hear manage our chems quite closely, but there are thousands, probably closer to hundreds of thousands, of pools that are over dosed on CYA from a diet of stabilised chlorinated products and I have never heard of kids presenting to casualty due to the accidental poisoning of pool water.

 

[Charlie227]

Here in Florida I find that a 70-80 CYA works best for my pool. Lower than that, the FC really takes a beating and it’s a constant SWG manipulation and some liquid chlorine dosing. Although I am fairly new to TFP, the concepts work and work well.

 

[woodyp]

Please have your wife consult WHO/CDC and get back to me with a link as to how much they say you can consume of pool water at that level (or any other) of CYA with no ill effects. Other than that, I will stand by my statement.

 

[sagosto]

Naw. TA is something you need to know because it affects the amount of chemicals you have to add to modify your pH, but you don’t need to try to lower it. It’ll come down as you add acid to lower your pH.

Thanks. I added a lbs or so of acid specifically to lower the TA as I didn't want PH to go to low. I'd rather make small changes and see how it impacts the tests.

Please have your wife consult WHO/CDC and get back to me with a link as to how much they say you can consume of pool water at that level (or any other) of CYA with no ill effects. Other than that, I will stand by my statement.

I'll jump right on that.

 

[jblizzle]

We have had discussion before about emergency drinking water and whether you could drink the pool water. Consensus was that should be a last resort, life or death option, partly due to the presence on CYA and of course other contaminants.

But, there is just no possible way for a kid to casually drink enough pool water to be harmful. They would have to be drinking nothing but pool water for a long time and if they are able to do that, then the parents should be looked at.

Certainly nothing wrong with the discussion, but these questions and discussions come up over and over so many members do not want to say it all over again when it can usually be found by searching the forum.

Bottom line, the TFP method works and is perfectly safe. I would say it is significantly safer than trying to follow the advice of any pool store (where we often see CYA in excess of 150-200ppm and they have you add all kinds of various potions). Perhaps we should all focus on changing the pool store industry

 

[tim5055]

I'm confused. The paper, right in the executive summary says:

Where chlorinated isocyanurates are used, levels of cyanuric acid in pool water should not exceed 100 mg/l.

So, as 100 mg/l is the same as 100ppm, why is our recommendation bad? It's less than 100.

 

[Deb04]

Sagosto,

If your household will be happy with 40-50, that really shouldn't be a problem. You may find that your SWG can't keep up with the demand and then you and your wife may have to discuss and maybe going to 60 or supplementing with bleach. I live in NH and the sweet spot for my pool is a CYA of 50. It almost seems like my pool balks at 60 or 70. After 11 years, I know my pool pretty well and I'm going to stick with 50, no matter how many times I get told it should be 70.

 

[sagosto]

Sagosto,

If your household will be happy with 40-50, that really shouldn't be a problem. You may find that your SWG can't keep up with the demand and then you and your wife may have to discuss and maybe going to 60 or supplementing with bleach. I live in NH and the sweet spot for my pool is a CYA of 50. It almost seems like my pool balks at 60 or 70. After 11 years, I know my pool pretty well and I'm going to stick with 50, no matter how many times I get told it should be 70.

Thanks. I am going to creep it up to 50 and see how things align. I am much better off today than a few weeks ago so I am learning as I go. It's amazing how much ppl don't seem to know the basics. My mom literally just dumps shock without any reason to do so. My father in law does that too - dumps tablet into it. No check. Just dump.

 

[jblizzle]

Thanks. I am going to creep it up to 50 and see how things align. I am much better off today than a few weeks ago so I am learning as I go. It's amazing how much ppl don't seem to know the basics. My mom literally just dumps shock without any reason to do so. My father in law does that too - dumps tablet into it. No check. Just dump.

If you are worried about CYA, keep your kids out of their pools!!! Although the low sanitizer level relative to the CYA is more dangerous.

 

[Deb04]

Why would there be a sanitation problem if he does asi do? I keep my CYA at 50 and CL at 6.

 

[jblizzle]

Why would there be a sanitation problem if he does asi do? I keep my CYA at 50 and CL at 6.

There wouldn't be, as has been stated multiple times.

There is really no disagreement here beyond whether CYA > 50ppm is safe. We know it is, OP is not sure.