TF-100 Test Kit Problem

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Mark92677

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Apr 24, 2010
21
Laguna Niguel, California
When conducting the Calcium Hardness (CH) test using the TF-100 Test Kit, I get pinkish precipitate in the solution when I add the R-011L reagent. When I then add the R-0012 reagent, I get no color change, regardless of how much I add. I don't add copper algecide to my pool, but I did the R-0012 add prior to the R-011L reagent anyway with no change in results.
What is the problem? :?:
 
Mark92677 said:
When I then add the R-0012 reagent, I get no color change, regardless of how much I add.
Click to expand...

Mind if I ask how much exactly is "regardless of how much I add"?

CA water is often high in calcium. Is it possible you're giving up too early? CH in the upper 400-600's isn't uncommon. Especially with pools chlorinated with cal-hypo at any previous point.

What is your pool's history? Can you post a full set of results?

If you're getting an actual pink result at first, you have some calcium, you just need to find the cap. I haven't ever seen pink. I get a dull brownish yellow at first when I test both the pool and the tap water. Pool is about 20ppm, tap is 2ppm. Neither turn anything close to pink when I begin the test. The test calls for a red to blue change (brownish yellow is a degree of red => blue, as I see it). I see a blue tint and then no further change with additional drops. The drop that turns it tinted blue is the value I record.
 
As described here, metal ions can interfere with the Calcium Hardness (CH) test creating the pink floaties you are seeing and making the endpoint fade or be less distinguishable. You can add some (say, 5) drops of R-0012 titrant first to the sample before you add the R-0010 calcium buffer or R-0011L indicator dye. Though you might still get some floaties, the endpoint should be more distinct.

If you think your CH might be high, then use a 10 ml sample size where each drop is 25 ppm (see this page for instructions on this where you use 10 drops of R-0010 and 3 drops of R-0011L).
 
Adding to what Richard posted, your thread from April of last year indicates a HIGH concentration of metals in the water......not black algae. If that was never resolved, it would certainly explain the "floaties" in the CH test.
 
duraleigh said:
Adding to what Richard posted, your thread from April of last year indicates a HIGH concentration of metals in the water......not black algae. If that was never resolved, it would certainly explain the "floaties" in the CH test.
Click to expand...

Yes this is true, I did have high copper content in the water. I completely drained the pool, flushed the plumbing with fresh water, replaced the filters and all of this after I had given the pool a wash with Ascorbic Acid to remove the copper stains.
So the pool has all new fresh water.

So far, nothing that anyone has said accounts for the precipitate (soft clumps) that are created when I add the R-0011L reagent, which of course follows the R-0010 reagent which has thoroughly been mixed in solution. The question is, what chemical reaction could cause this formation of precipitate. The test instructions and the test kit web site don't even address this possible reaction. :(
 
chem geek said:
As described here, metal ions can interfere with the Calcium Hardness (CH) test creating the pink floaties you are seeing and making the endpoint fade or be less distinguishable. You can add some (say, 5) drops of R-0012 titrant first to the sample before you add the R-0010 calcium buffer or R-0011L indicator dye. Though you might still get some floaties, the endpoint should be more distinct.

If you think your CH might be high, then use a 10 ml sample size where each drop is 25 ppm (see this page for instructions on this where you use 10 drops of R-0010 and 3 drops of R-0011L).
Click to expand...

I'm not so sure that the CH is high as it appears that some other chemical reaction is occuring that is interfering with the test, or there is something wrong with the reagents.
I'll try adding 5 drops of R-0012 prior to and see what happens.
 
Mine does the same thing, never turns red, just pink and has never turned blue, I have put a half a bottle of 0012 and it went clear. What I have been doing is going to the pool store, they use Taylor drops and I watch them do the test counting drops and it turns red and then blue and I dont know why, I use there number for CH and mine for everything else
 
chucklh said:
Mine does the same thing, never turns red, just pink and has never turned blue, I have put a half a bottle of 0012 and it went clear. What I have been doing is going to the pool store, they use Taylor drops and I watch them do the test counting drops and it turns red and then blue and I dont know why, I use there number for CH and mine for everything else
Click to expand...
I assume you are using the TF-100 for testing CH.

It is, in fact, the Taylor test you are performing. It is their chemistry. I can't explain why the pool store is getting results and you are not but the tests are identical in every way.
 

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chucklh said:
Mine does the same thing, never turns red, just pink and has never turned blue, I have put a half a bottle of 0012 and it went clear. What I have been doing is going to the pool store, they use Taylor drops and I watch them do the test counting drops and it turns red and then blue and I dont know why, I use there number for CH and mine for everything else
Click to expand...
When I had a similar effect, I was told by Richard and Jason that high FC could be the reason. What's your FC?
 
Make a sample of 50 % pool water and 50 % distilled water. Mix well. Follow these steps to test:

1) Rinse and fill large comparator tube to 25 mL mark with water to be tested.

2) Add 10 drops R-0012. Swirl to mix.

3) Add 20 drops R-0010. Swirl to mix.

4) Add 5 drops R-0011L. Swirl to mix. If calcium hardness is present, sample will turn red.

5) Add R-0012 dropwise. After each drop, count and swirl to mix until color changes from red to blue.

6) Add the original 10 drops of R-0012 to the number of drops needed in step 5, and multiply the total number of drops by 20. Record as parts per million (ppm) calcium hardness as calcium carbonate.
 
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