CYA testing

[Charlie_R]

I was in the pool for my daily therapy, and needed to do my monthly testing.

When I got to the CYA test, I tried something a little different. As I was pouring the mixture into the test cylinder, the bottom half of the cylinder was in the water. I came up with 40 ppm that way, so tried it again (same sample) with the cylinder out of the water. Same result. Repeated several times. It appeared to be easier to read with the bottom of it in the water, allowing the light to enter it from all directions.

Has anyone else tried this? If so, what are your findings?

 

[JesseWV]

It would be interesting to see how the standard 50 ppm solution reads using this method.

 

[gtemkin]

I think one of the intents of the recommended test of holding it at your waist is that you're less likely to be blocking light with your hand. Unfortunately there's a natural tendency to try and get a better look by holding it up higher, which results in bear-pawing the entire cylinder and blocking much of the light. I get pretty consistent values so long as I concentrate on keeping it low and holding it by my thumb and forefinger only, with pinky out.

 

[JesseWV]

I also noticed that slightly tipping the tube helps to reduce the reflection of the shadow of your head, which can sometimes look like the dot.