Delayed reaction with chlorine tests

[papa6]

In the spring of 2006 I purchased a PS234S testkit (serial # 6616) and was extremely pleased with the accuracy and ease of use. This year however, I have become totally frustrated when testing chlorine. When I test using the (OTO), my test starts out totally clear ( zero chlorine), then after a minute or so it starts turning yellow and starts climbing the chart. When I test using the (FAS/DPD) method I notice that when the pink color disappears it will reappear in a minute or so.
I keep my test kit in the house and have always rinsed the test tubes before and after every use. I always follow the ">GETTING GOOD RESULTS" instuctions.
My problem is I really don't know what is accurate and didn't have this problem last year.
PLEASE, I beg someone to tell me what I'm doing wrong!!!

Thanks, Dick :confused:

[chem geek]

Dick,

By any chance is the sample water temperature cold? Do you see the same problem if you let it warm up to room temperature (cap the top of the sample container while waiting for it to warm up).

Richard

[papa6]

Richard,
Yes, the water temperature is cold, 70 degrees or so......I just opened last weekend and have not fired up the heater yet. I will cap a sample tomorrow and let it warm up before testing. THANKS A BUNCH for the tip!!!!!! I will let you know how it comes out. Thanks again!!!
Dick

[waterbear]

Also, the OTO test for total chlorine (turns yellow) can take up to a minute or two to fully develop

[papa6]

Chem geek and waterbear, I would like to thank you sooooo much for the insight you gave me on testing my water. I would never have thought that my water being cold could have an effect on the testing. The water is now warm and everything is working great! This was a simple answer for you, but a frustration for me, thanks again for taking the time to help me. This is why this forum is GREAT!!!!

Papa6