testing low levels of CYA

[carlos31]

Is there anyway to test low levels of CYA? 0 to 30ppm.

The Taylor kit seems to go down to 30ppm and I am not sure about the TF-100.

thanks,

 

[giulietta1]

Hello and welcome, Carlos!

There is such a test but I don't think it's in the TF-100. It should be available thru the Taylor website; I believe it's rather expensive.

The "experts" can tell you more, but I knew *something* about the topic so I thought I'd chime in. Why do you need to test at those low levels?

 

[kidsluv2swim]

I believe the TF-100 tests to 20.

 

[duraleigh]

Correct. The Taylor 2006 tests down to 30 and the TF-100 tests down to 20.

I am not aware of a test lower than that but it may exist.

 

[chem geek]

Yes, the TF100 tests down to 20 ppm as does the Taylor K-1720 (shown here) but this latter CYA-only kit retails for about $48. Yet another advantage of Dave's TF100 kit over the K-2006.

 

[JasonLion]

There are some mid-range colorimeters that claim reasonable accuracy at fairly low CYA levels. I find some of their claims difficult to believe, but I have never actually tried them. The more reasonably priced colorimeters aren't at all good at measuring CYA levels.

There are some tricks you can play with the standard test. For example, evaporate off three quarters of the water in the sample and then test that. But doing this carefully enough to be even slightly useful is difficult.

 

[carlos31]

Thanks for the replies. I guess I will just keep track of low levels based on how much I put in since CYA never comes out without water loss.

In regard to "why?". I am about 3 weeks from plaster (my own build). I will be using a Liquidator (with Rabbit's modifications), and an Intelliflow 4x160 running at low speed 24/7. I am going to attempt to provide constant flow and constant chlorine injection to the 45K (estimate) plaster pool. After reading the following article, it looks like low levels of CYA may be appropriate for my setup.

Cyanurics ~ Benefactor or bomb?
Removed attachment and replaced with a link. JasonLion

Of course, the CYA levels and chlorine loss from load and sunlight will need to be played against each other and adjusted accordingly. I am thinking that CYA at 5-20ppm or so with low levels of chlorine being continuously added to the water will allow me to use as little of each chemical as possible; which is basically the goal of BBB.

It sounds plausible to me but until I get into the real world I won't know for sure. I figure it won't hurt to try since I can always add more CYA and adjust the LQ accordingly. Is anyone familiar with the attached article? Are there any pitfalls or issues you may be able to point out based on your experience?

 

[JasonLion]

You should read this topic before making use of any of the ideas in that article. There is lots of misinformation there, along with a bunch of good information. The conclusions you are drawing are mistaken, based on some incorrect information in that article.

What you are planning isn't really a great idea. It can work, but it requires you to run the pump during all sunlight hours. It is really a much better idea to have CYA between 30 and 50. You will use less total chlorine and won't need to run the pump all day.

 

[carlos31]

Thanks for the link, I didn't realize this article had already been discussed. There is also a great link in that thread to another thread in the Deep End for those who really want to understand the chemistry.

I still intend to run the Intelliflo 4x160 at a low rpm, energy efficient speed which will take most of the day to create one turnover at 45K gallons, so I figured why turn it off. That was discussed on this thread.

http://www.troublefreepool.com/hayward-tristar-variable-flo-vs-pentar-intelliflo-t4005.html

One thing I took from the articles you directed me to is that each pool varies in its chemistry and there are several examples of pools which don't follow the "norms". So I know I will need to do some experimenting. I also gather that your basic point is that my bleach costs will certainly exceed my CYA costs if I don't maintain 30 to 50ppm CYA.

Thanks for the great information.