Did my DPD powder die?

[rv4hess]

In the last few days we had some thunderstorms with a few inches of rain. Afterward I noticed our pool was cloudy with a hint of green.
Using my TF-100 test kit, when I added the DPD powder to the pool water it did not turn pink at all.
Knowing no FC means shock the pool, we made a chlorine run and added 6 gallons of bleach. (17,500 gal./ CYA 50)
Three hours later I went to test again and still no pink to start with.
To confirm, I tried our simple Taylor K-1000 chlorine test. When I started adding the R-0600 it turned a wierd shade of orange.
(I assume this means we do have a great deal of TC?).

Could the pool have sucked up all the FC that quickly or did my DPD powder go bad?
The test kit is only about 9 months old and has been stored inside.
Taylor's website says all their products are engineered to last for at least a year under normal care.

P.S. while typing this I realized I should have gone ahead with the CC test. I will add the results in a few minutes.

Thanks,
John

 

[rv4hess]

Update one, testing again this morning with the FAS/DPD it shows a correct indication of 26 ppm FC and a CC of 1.
My guess is that when I tested last night, (3 hours after adding the bleach), I must have pulled the test water from a circulation dead spot and the chlorine had not had time to dilute throughout
Any other theories?

Thanks, John.

 

[mynewpool]

From what I have read, or I could be wrong which correct me if I am. At high FC levels when using the powder, you may need to add a little more than normal to get the sample to turn pink.

 

[Buford]

I've never had this kind of issue. But, Taylor has videos which might be helpful, the one for fas/dpd under the k2006 might answer your question, it does mention the color returning to clear. Their site is here http://www.taylortechnologies.com/produ ... deshow.asp click on "pools and spas" then find your video.

 

[duraleigh]

It is a guess but I would be pretty confidant it "bleached out" with that first test. 3 hours should have been PLENTY of time to circulate.

As posted in other threads, that powder will darken over time...even getting charcoal gray looking but it almost always turn the solution pink which is all that's required for the test. However, if the FC is VERY high (and yours was), it will often take 2-3 scoops to get that pink tint.

 

[rv4hess]

It is a guess but I would be pretty confidant it "bleached out" with that first test. 3 hours should have been PLENTY of time to circulate.

As posted in other threads, that powder will darken over time...even getting charcoal gray looking but it almost always turn the solution pink which is all that's required for the test. However, if the FC is VERY high (and yours was), it will often take 2-3 scoops to get that pink tint.

I'm not familiar with "bleached out".

What was odd to me was that last night when I put the powder in it did not turn to pink at all, just stayed clear.
This morning when I added the powder it was as pink as I have ever seen.
And it turned pink right as the granules hit the water. The chemicals are obviously not at fault. It must have been operator error.
My theory is that the spot that I took the sample from is probably the worst circulation point.
If I ever have this problem again I will try two things to help solve the issue;
A) try more powder in the sample.
B) sprinkle a few flakes of powder at various places in the pool and see if the chlorine could be hiding somewhere early in the diffusion process.

Thanks for the good info,
John