Taylor calcium hardness test wierdness

Rich Purdum

Active member
Mar 9, 2010
I just performed the Taylor Calcium Hardness test (the blue top bottles) and got a strange result. The solution turned red as expected after 20 x 0010 and 5 x 0011L. After adding about 35 drops of 0012, the red started to precipitate into small globs that remained in suspension while the surrounding water was clear. After 45 drops I never did get blue which indicated the test is complete. Before I queue up at Taylor to ask what is going on I thought I would ask here. And no, the chemicals are not stale, I took a water sample to my local Leslie's and the same thing happened to them (with the same test). One of the guys there said maybe my high chlorine level was bleaching out the result. (I was in a slow process of bringing up a new pump and was keeping chlorine on the high side since it was running only a few minutes a day.) Chlorine is back to .5-1.0 and still the same result.

Anyone have an idea as to what is going on? Apologies if this has been asked and answered elsewhere in this forum...I could not locate it.

Edit - previous post stated "green tops" and 2 x 0010. S/B "blue tops" and 20 x 0010. Guess my TA and CA were trying to mate! Went back to retest using the suggestions and noticed my oops :oops: ! Now I'm out of 0012! Back to the store....


LifeTime Supporter
May 19, 2009
Dallas, TX
Possible anomalies with the CH test...
2. Red flakes or dots in the solution....although solution has turned from blue to red. (I've seen this on the forum as well) It is caused by the presence of magnesium in the water and can be ignored. The blue endpoint is still accurate and magnesium is, for the most part, not a concern in pools.

3. Endpoint goes from Red to Clear (I don't know if we've seen this reported here) Again caused by the presence of magnesium. It is corrected by redoing the test and adding 8 or so drops of R-0011L instead of the suggested 5 drops.
Here is a possible solution...

Rich Purdum

Active member
Mar 9, 2010
Still getting a precipitate in the test

Tried the Taylor suggestion of adding 5 drops of R-0012 to the sample before adding 0010 and 0011L. Did get a more bluish end result but still got the red particles. Let the solution sit for a bit and the red stuff settled to the bottom of the sample tube. I've submitted a query to Taylor so we'll see what they have to say. I also tried adding more 0011L and again got the particles. My 0011L is old but since Leslie's got the same result I don't think that's it. The 0011L from my bottle is almost "goopy" and drops straight to the bottom of the tube. It takes a fair bit a swirling to get it to dissolve. Is that normal?

Melt In The Sun

TFP Expert
LifeTime Supporter
Oct 29, 2009
Tucson, AZ
The R-0011L that I have is also very "goopy". I have the same issue with precipitate forming, so am interested to hear if anyone has a solution. Adding R-0012 first didn't help for me either.

Rich Purdum

Active member
Mar 9, 2010
Response from Taylor

Here is the full text of the reply message from Taylor. I've made bold the portions of major interest.

Bottom line:

1. The red specs are magnesium and are normal, more normal in some waters than others. This was mentioned in an prior reply to this thread.

2. You can try to overcome the red specs by increasing the indicator 0011L from 5 drops to 8 drops. This seems to be the first thing to try.

3. If this does not work, try the procedure of adding 5 or 6 drops of 0012 before adding 0010 and 0011L.

4. 0011L thickness is normal (as are apparently other "indicator" solutions). As I recall one of the TA solutions is thick.

I need to figure out what took my CH over 400 when it had been running substantially less than 400 last year. I did get a note from the water company in the fall about the water becoming "harder" for a few months as they were doing maintenance on the system. Also, there was a lot more rain this season. The local NOAA station has recorded over 22 inches for the year (not sure when it starts here in Northern California). If I can get the Taylor test to function and get a reading within reason, I may just wait the normal refilling for evaporation to bring it down.

Meantime I'm off to Leslie's for fresh test chemicals.

Begin quote

Dear Rich:

Thank you for your email, it was forwarded for my reply. I would first
advise you to replace the R-0011L because from the lot number you
provided it indicates the reagent is past its useful shelf-life, which
is three years. Even if these corrective actions I recommend work you
may still get an inaccurate reading because the reagents is old. The
R-0012 is fresh, but I am unable to determine the condition of the
R-0010 because the lot number submitted is either incorrect or it is

The cause for the interference in the pool store and your sample is most
likely due to metals in the water
. One way to help alleviate the
interference in this case is to increase the indicator from 5 to 8
. If you are still unable to reach a blue endpoint rerun the test
and try adding 5 or 6 drops of titrant (R-0012) to the sample before
adding the buffer (R-0010) and indicator (R-0011L), then proceed
normally with the test.
Include the number of drops of titrant added at
the beginning of the test when counting the total number of drops
required to reach endpoint.

Ensure you reach a permanent blue endpoint. There are some gradient
colors and shades of blue during the titration process. You can ensure
you have reached the endpoint by adding an extra drop when you think you
have reached the endpoint. Note if the blue color changes. If it does
then you haven't reached the endpoint. If it doesn't then don't count
the extra drop.

The red specs in the sample are perfectly normal. This is just magnesium
coming out of solution. It is not an interference and you will notice it
more in some waters compared to others. Also, do not be concerned with
the viscosity of the R-0011L. The indicators are more thick than the
titrants and buffers.


Jarad Proctor
Customer Service Representative, Technical Support

end quote


LifeTime Supporter
Jan 11, 2009
Cupertino, CA
Rainwater is really optimal for dilution; zero everything (except pH). But it sounds like you need to pick up some new reagents too. That should help the test behave better!

Rich Purdum

Active member
Mar 9, 2010
Back in business

Picked up a fresh set of CH and TA (Leslie's has a coupon for 50% off)...all of mine were 3+ years old. Used the procedure of adding 5 drops of 0012 before proceeding with the normal test and got a good blue at 35 drops (albeit with red specs). Getting the 5 drops of 0011L to mix in took a bit more effort. Could not find my old log sheets but that's about what I recall getting in previous years. I need to get the pool back in balance after the winter rains so I'll keep re-testing as I go.