Help with Calcium test

[waterbear]

Richard, I am not that familiar with the acutal chemitry that happens with the calcon indicator (or eriochrome black or any of the other indicators used in complexometric titrations) to really answer that. I do know that pH indicator is not that critical and might give a more intense color if a bit more is used but I wonder if adding more would affect the result since the color change is part of an acid/base reaction and the indicators are themselves weak acids/ bases. There have been some issue with the indicator used in the Aquachem 6 way kit for total hardness and I have had good results adding indicator until the solotion turned pink (and have cross checked it against the Taylor and Ben's test) but others have reported inaccurate results doing the same thing. The TA test colors are pretty intense and the color change from green to red is very distinctive so I don't think that test is an issue. The one in the aquachem kit goes from blue to yellow and is a bit hard to read. Perhaps more indicator might work here. I believe the indicator in that test is possibly bromthymol blue. You are the chemist...I am just an amatur!

[chem geek]

Thanks for the info. And though I know you were joking, just for the record so others on the forum know, I'm not a chemist, at least by trade. I majored in it in college (along with physics) and I enjoy it somewhat as a hobby (hence "chem geek").
Richard

[waterbear]

I was a chem major for 3.5 years (I WAS going to become a chemist) and then switched and got my degree in broadcast journalism with an education minor! DON'T ASK!