PSA : Check your Reagent Expire Dates

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
17,378
Tucson, AZ
So yes, it can happen to even the most seasoned of us....

This morning I was out by my pool testing my water using my K-1004 "Troubleshooter" test kit after making some adjustments the day before. It's nice because I can easily do pH, TA and FC/CC tests with it. The chlorine test is a color comparison based on DPD (pink) and comes with the R-0001 and R-0002 reagents. The R-0001 reagent is a buffer and pH stabilizer with some chelating agents to remove metal interference and the R-0002 is the DPD indicator solution. R-0001/R-0002 together can be though of as a liquid version of the R-0870 powder. With the right comparator and some good lighting you can easily distinguish FC levels.

A few days ago I had measured FC and it was quite low from what I expected it to be coming out of spring and into warmer weather. Usually this time of year I can easily expect 5ppm or more, a very distinct reddish/pink color. It was closer to 2-3ppm and so I added some liquid chlorine (about 4ppm worth) and turned my SWG up to 50% and my runtime to 6 hours (It was previously at 35% and 4 hours). I did know my CYA was a little low so I just assumed that the recent spat of warm weather and high UV was eating up my FC faster than I was producing it. My CYA usually drops a bit over winter and when I measured it I was getting values of 60-70ppm, I typically run at 80-90ppm. SO I loaded up a sock with granular CYA to add another 10ppm and let go for two days.

Fast forward to this morning and I measure my FC....less than 2ppm and the color looked weird. Not the usual light foggy-pink but more of a brownish-pink color. Scratched my head a bit (and my other end too) and then decided to test again. Definitely the weird light brown-pink. As is usually the case, I went though all of the impossible theories first .... bad SWG, leaking pool, dead bear in the deep end, space aliens removed my pool water, etc, etc. Then I tilted over the R-0002 bottle a little bit to look at the fluid in the tip. Sure enough, the R-0002 reagent was a brown color and not at all the usual clear color. I twisted the bottle and, sure enough, the Exp Date read "10/2017".....hmmmm, so maybe it wasn't space aliens after all (although they do exist as per recent DOD press releases...but that's another topic). But, being a man of "science" I decided to follow Occam's Razor. I also remembered that when I did the first test before adding chlorine and bumping up my SWG and CYA, I had gotten three drops of R-0002 out of the previous bottle before adding two drops from this compromised bottle. So the original test that led me to make some of the changes had 3 drops of good reagent and two drop of bad reagent which was enough to give it the right pink color but at a much lower level.

After realizing that space aliens did not take my pool water (but they probably messed with the order of my spare reagents in my cabinet...), I used my DPD powder test chemicals (R-0870/R-0871) and found that my FC was actually at 7ppm (35 drops on a 25mL sample). That's typically higher than I like to run (by a factor of 2), but I felt much better. I went to my mom & pop pool store that sells Taylor reagents and got some fresh bottles of R-0001/R-0002. I then retested and, sure enough, the color of the test sample was a blazing hot red/pink which is way over the 5ppm color block and, if my color-memory serves me right on the big-boy comparator, easily is the 7.5ppm match.

So, long story short, keep an eye on your expiration dates, they matter......

Happy pool'ing
 
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JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
17,378
Tucson, AZ
Taylor would tell you none of them are good past their expiration but that’s being cautious because there’s no way you control how people store and handle them.

General speaking the acid/base reagents (R-0005/R-0006, R-0015/16, R-0009, R-0010, etc) will last a long time if you are careful with them and store them properly.

R-0007 thiosulfate is good for a long time.

pH indicators like R-0004, R-0008, etc, are fairly stable.

Titrants like R-0871 and R-0012 can easily get contaminated by air (oxidation) and so won’t last long.

R-0001 and R-0870 (DPD indicator) are easily oxidized by air and should be kept tightly sealed.

R-0011L (calcium indicator) will go bad over time and separate out of solution.

Finally R-0013 (CYA) ... indestructible unless you inadvertently contaminate it.

The silver nitrate titrant in the salt test kit is light sensitive. As long as it’s kept cool and dark, it will last a long time.
 

LFrankow

LifeTime Supporter
Sep 27, 2012
608
Medicine Hat, Alberta
I started shopping replacements reagents a few weeks ago, in the end I ordered up a 2006c with salt test. Seems like a good maintenance plan to reorder a new kit every 3rd spring. I plan on alternating it with solar cover replacement to spread the high cost of pool maintenance down :)
 

ruger311

New member
May 13, 2020
2
Arcadia, OK
First post but I am happy I found this thread because I’m having a bit of an issue with the FC coming in almost tan colored. Thought things were way off but tilted 002 over and it’s kinda brown colored. Hoping that’s it as everything looks good in the pool. TA a bit high 140-150 though.
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
17,378
Tucson, AZ
First post but I am happy I found this thread because I’m having a bit of an issue with the FC coming in almost tan colored. Thought things were way off but tilted 002 over and it’s kinda brown colored. Hoping that’s it as everything looks good in the pool. TA a bit high 140-150 though.
If it’s brown, it’s compromised. Time for new reagents.
 
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ruger311

New member
May 13, 2020
2
Arcadia, OK
No dates on a few bottles, just lot numbers. Likely old old old. Found one with a 1/2021 date on it. Purchased a home with a nice pool out back, just don’t wanna screw it up too bad. Old homeowners said all they did during opening is fill, throw in two gal of MA, run pump overnight, throw in another gal of MA, then shock once. They threw in pucks in chlorinator and let it rock.
I’ll replace the kit to get a fresh start.