CH Test Question

[iwannapool]

When using the Taylor 2006 test kit for CH I get a wierd reading/response. When you add the drops that are suppose to turn it red I get a very light pink and then the pink starts to form into tiny droplets suspended in a clear solution.

I then start to add the the drops to turn it blue and I get to a point where it turns more of a light purple color. To the best of my ability I get a reading of about 250 ppm. I tried it on my softened house water and it worked just as the instructions described.

I have an IG vinyl/SWG pool, temp is ~85 F, FC=5.0, CC=0, pH= 7.5, and TA=140. My CYA should be about 50 ppm but I added it last Saturday so I've been waiting to measure it so it has a chance to completely dissolve.

Anybody know why my CH test acts so strange? Thanks!

[chem geek]

Try adding 4 of the titrant drops (the ones you count) first before adding the calcium buffer and indicator. Then add those 4 to your count of drops you add after the indicator. See this link for more information about this. Metal ions can interfere with the test though usually it just results in what is known as a "fading endpoint" where the color change does not stay.

Richard

[iwannapool]

Thanks for the suggestion, I will try this to see if it works. It also got me thinking when I went to the link you provided. When my pool was being filled the pool builders assistant accidently put double the amount of algaecide into the water.

Is it possible that this is interferring with my CH testing?

[chem geek]

I don't think the algaecide will interfere with the CH test.