Help with Calcium test

[torsie]

I don't test my Calcium very often and when I did today it barely turned a pink cast. More of a clear with pint tint. So I never did really get a blue color either. I managed after 28 drops to make it a clear color with a blue tint.
Any ideas?

[torsie]

Bumping this up hoping for some help.
Should I be concerned that I dont' get anything but a slight pink tint when I test my calcium?

[waterbear]

The colors from the test are not very intense. They are very pale so you are fine.

[chem geek]

Evan (waterbear),

I wonder if one could use more indicator drops (10 instead of 5) in the test for a more intense color. Normally the amount of indiciator drops doesn't significantly affect the test result unless the amount of indicator overwhelms the amount that is being tested or unless it influences the test itself (possibly in pH). I suppose this is a simple experiment any of us could do with the pH, TA and CH (and FAS-DPD?) tests by first measuring the normal way and then repeating (with a fresh sample) using double the amount of indicator to see if there's any difference. If there isn't, then perhaps those who want a more intense color could use this technique. They'll be replacing their indicator reagents more frequently, but that might be a worthwhile expense.

Richard

[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!