Is CYA of 70 ppm too high?

[chem geek]

Well I can tell you that he's wrong. The ongoing use (addition and consumption) of bleach or chlorinating liquid or any other hypochlorite source of chlorine will not raise the Total Alkalinity (TA). It will raise the salt level as will all sources of chlorine though the hypochorite sources increase it more. I will say that with an Endless pool in operation there is a lot of aeration so that will tend to make the pH rise quickly if the TA is higher so the way to mitigate this is with a much lower TA and, if needed, the use of 50 ppm Borates.

Take a look at Cyanuric Acid and compare it to Dichlor and Trichlor. Do you notice any similarities? Essentially, Dichlor has two of the three hydrogen attached to nitrogen replaced with chlorine while trichlor has all three hydrogens replaced with chlorine. When in water, the Dichlor and Trichlor release some of the chlorine into the water forming hypochlorous acid. The core CYA ring doesn't go anywhere so the CYA level absolutely rises. To say that stabilized chlorine does not increase CYA is completely wrong and to say that it won't affect the effectiveness of chlorine is also wrong.

To be continued in next post since there is a limit of 5 URLs per post (ARGHHH!!!!).

[chem geek]

(continued from previous post)

The relationship between chlorine and CYA has been known definitively since at least 1974 as described in the scientific paper in this link (you can read the intro section in the paper since it is somewhat non-technical). As for CYA's effect on chlorine effectiveness, there are many papers on this from the 70's and 80's as shown here, here, here, here and

(to be continued on the next post because of the 5 URL limit!!!)

[chem geek]

(continued from previous post)

here.

I suggest you read the Pool School to learn the truth about what really happens in pools. The pool and spa industry has not been well-trained and even the official courses (NSPF CPO and APSP TECH) still withhold certain basic facts or disclose misleading information such as chlorine vs. pH charts that simply do not apply when CYA is present. So don't blame your pool stores -- they are just getting incomplete or incorrect information from the manufacturer sales reps and from an industry that doesn't seem to care very much about integrity. I'm trying to change this, but am amazed at the amount of resistance to even disclose basic chemical facts such as how much the CYA rises from stabilized chlorine or CH rises from Cal-Hypo, let alone the chlorine/CYA relationship.

Richard

[Jeffm]

Sodium Hypochlorite = Liquid Chlorine, right?

[chem geek]

Yes. Sodium hypochlorite is in both bleach and chlorinating liquid aka liquid chlorine (though technically it's not really liquid chlorine since chlorine at room temperature is a gas, but people call it that anyway).