Need help with Taylor Calcium test kit

[JimK]

First, the Taylor TA test turns from green to red. If it is turning purple then you have a biguanide (SoftSwim, Baquacil) pool!
The color change on the CH test is from a pink to a sky blue. This document from the Taylor website illustrates this color chagne and info on the color changes of the TA test

Sorry, must have had purple on the brain. You are correct, TA; green to red. We had the pool installed new in 2004 and it has always been a chlorine (via SWCG) pool.

http://www.taylortechnologies.com/Ch...P?ContentID=35

Thanks for the link. My sample doesn't turn nearly as dark as in the pictures (it looks much closer to #1 than #2). Directly comparing those pictures, I can just make out the difference between #2 and #4.

If you are having trouble seeing the color change then add a few more drops of the indicator solution to your sample or try using a 10 ml sample where each drop is 25 ppm CH. TO do so you would add 10 drops of calcium buffer to the 10 ml sample, 3 drops of indicator, and then titrate.

Thanks, I'll give that a try. So adding enough indicator to get it dark enough doesn't affect the results? I'll also try the suggestions on the Taylor site regarding if metals are present.

If your color changes to a purple color you reverts you probably have metals in the water (a common interference).

I'm sorry, I don't understand this statement.

The Alex system is designed to maximize chemical sales for your Bioguard dealer and is not to be trusted. IT also uses a strip reader so it cannot give you a calcium hardness reading, only a total hardness reading.

Yeah, I kinda figured as much, which is why I would really like to find a way to test calcium that I can read. I know low calcium isn't an issue for vinyl pools (which I have), but I understand I don't want it too high.

Speaking of the Total Hardness reading, is it possible for Calcium Hardness to higher than Total Hardness? Or is Calcium Hardness always going to be lower than Total Hardness (if so, I'm probably OK given my Total Hardness usually stays around 250ish).

The calcium hardness titration of calcon indicator or one of the eriochrome indicators with EDTA in an akaline solution to remove the magnesium hardness is the standard test for calcium harndess.

Eeeek......what did you just say? Sorry, that went completely over my head.. Are you saying that the Taylor type test is the only reliable one available to me?