LaMotte ColorQ Water Tester

[waterbear]

inverting the vial 3 times is the correct procedure but you have to make sure the tablet is fully dissolved. Also high water temp will give a lower reading since the precipitate will be more soluable so having the sample at the correct temperature is important. We get many customers who leave a water sample in their car all day! (I TRY to tell them that this will affect the test results but some of them just don't care.) The first thing I always do is to take the temp of the sample and if it's above 80 degrees I stick it in our freezer at work for a few minutes to bring it down before I test it.

[donaldm823]

inverting the vial 3 times is the correct procedure but you have to make sure the tablet is fully dissolved. Also high water temp will give a lower reading since the precipitate will be more soluable so having the sample at the correct temperature is important. We get many customers who leave a water sample in their car all day! (I TRY to tell them that this will affect the test results but some of them just don't care.) The first thing I always do is to take the temp of the sample and if it's above 80 degrees I stick it in our freezer at work for a few minutes to bring it down before I test it.

I second Waterbear's comments and add that based on my 2 months experience with the colorQ, you need to let the CYA sample sit for at least 5 minutes before reading or it will read low and get that sample below 78F. Also, if analyzing samples with chlorine higher than 4ppm, you need to let all of the samples with reagent added sit for a minimum of 2 minutes before reading with the meter or you may get erroneous readings on FC, TC, and pH reading. My CH always reads low as compared to Taylor, but it's still inside the +/- 40ppm window

[Amir]

Donald,
don't you think LaMotte should or would have indicated in their instructions the longer length of time for samples. I can understand that they want to make it as simple as possible, but at least a footnote? last night I put a sample of the water with a thermometer in the refrigerator until the water was at 75F and tested for CYA according to their test procedure. The results was a CYA of 12. ups picked up the unit along with a sample of my water. I hope that this problem is just specific to my colorq and other unit or the replacement one will be more accurate.
Regards

Amir

[donaldm823]

Donald,
don't you think LaMotte should or would have indicated in their instructions the longer length of time for samples. I can understand that they want to make it as simple as possible, but at least a footnote? last night I put a sample of the water with a thermometer in the refrigerator until the water was at 75F and tested for CYA according to their test procedure. The results was a CYA of 12. ups picked up the unit along with a sample of my water. I hope that this problem is just specific to my colorq and other unit or the replacement one will be more accurate.
Regards

Amir

Amir
Understand your frustration, and yes LaMotte could improve the instructions after some run time. I suspect they were not aware of the intricacies of this new tester. I for one learn something new week about how to make my analysis results repeatable. Just today, I resampled for CYA after getting a 25ppm result after a long string of 38ppm results for the past month. Today, I shook the sample vice going up and down 3x, and got a 45ppm result, which is exactly what my Talor black spot test indicates. I believe based on other forum threads, that the CYA sample is the "toughest" for the colorQ since it really is a turbidity test of sediment vice a chemical reaction that results in a color