CYA Test

[jwgillis]

The only dumb question is one that is not asked. Therefore ... the following:

The same chemicals are used in the Lamotte "black dot" CYA test and my brand new TF100 test kit. However the instructions to mix are different. Lamotte "black dot" CYA test says to shake the mixing vial for 1 minute, let set for 3-5 minutes, shake once, and then read in the viewing tube. TF100 says to mix, wait at least 30 seconds, shake once more and then read in the view tube.
I am a recent convert to the TF100 and am having difficulty with the CYA "black Dot" test. I am following the TF100 instructions but have always had trouble with the "black dot" test.

Question: Are the TF100 instructions all I need (except experience) to conduct a reliable CYA "black dot" test?

 

[JasonLion]

This has a lot to do with water temperature. Cold water takes longer to react, so it needs more time to sit before you read the test. If the water sample is nice and warm, the TF100 directions are fine. But if the water is cold, the Lamotte directions make more sense.

What I do is: if the water is below 70 degrees I warm the sample up to indoor room temperature first, mix for 30 seconds, leave sitting for 2 minutes, shake for 10 seconds, read the result.

 

[jwgillis]

Jason,

Thanks ... water is 86 degrees so TF test is what I will continue to go with.

Another question (I'm new ... not sure this is the correct way to ask)

My new TF test kit says just to add the drops for the calicum hardness test ... no instructions to swirl or mix. Is this correct?

 

[JasonLion]

On the calcium test you add R-0010 and swirl to mix, add R-0011L and swirl to mix, then add R-0012 one drop at a time swirling to mix for several seconds (5 to 30 seconds) after each drop. Mixing longer after each drop of titrant makes the results more reliable and avoids fading endpoint problems.

 

[Guest]

I do the CYA test following the LaMotte directions no matter what the temp. I also recommend swirling after each drop of titrant in the CH test for at least 20 sec. or using a magnetic stirrer.