When performing the CH test (with a 10 ml sample and using 3 drops of the 0011L) my sample barely turns violet/red. It's extremely faint. Is this normal? It's very hard to tell when the color changes to blue and when it does change you can barely tell. The reagents are about 18 months old, but they acted this way right out of the box.
TF 100 CH test
- Thread starter HouTex
- Start date
What happens if you do the test with a 25ml sample and 5 drops?
I never see a dark red, but it is pretty obvious when it turns blue.
Has it stained the bottle?
I never see a dark red, but it is pretty obvious when it turns blue.
Has it stained the bottle?
Because of my high CH I have never tried the 25 ml sample. I'll give it a try. The R-0011L is pretty thick but I don't think it really stains the bottle. Again, it came that way and it hasn't changed consistency or how it colors the water sample since the time it was purchased.
Go ahead and put 5 drops of the color indicator in. It will not affect the results, and you can see the endpoint much better. You can confirm this by completing the test with the three drops as usual. After you do that, put a couple of more drops in to confirm what I said. If you are at endpoint, it will just be a darker blue. This is something we do in the water treatment world as S.O.P. on a daily basis, even for low level hardness testing. Please note that this is ONLY for the color indicator.
I have a kit that is over 3 years old and all the reagents still seem fine as well.
Have you read the extended test instructions? Wondering if something there may jump out ... like you are seeing a fading end point or something.
extended-test-kit-directions-t25081.html#p206396
Are you using the Speedstir? If so, I would suggest NOT using the built in light.
Thanks for the info Brushup, I was thinking adding more of the color would not hurt, but was not sure.
Have you read the extended test instructions? Wondering if something there may jump out ... like you are seeing a fading end point or something.
extended-test-kit-directions-t25081.html#p206396
Are you using the Speedstir? If so, I would suggest NOT using the built in light.
Thanks for the info Brushup, I was thinking adding more of the color would not hurt, but was not sure.
jblizzle said:
Don't use the light? Without the light it was even worse for me to see!
Yes, I read the extended instructions and tried those procedures as well. Same result.
I think the light ends up washing out the light colors ... make it very hard to see the end point of the FAS-DPD tests. Just my opinion though.
You're welcome Jason, no sweat.
I want to second Jblizzle on not using the light. At least to start, and I strongly discourage it for new users. Reason being is that the light washes out the true endpoint colors. You can see them best with strong ambient light, particularly against a white background. In a lab setting, these types are run in a white ceramic dish, under bright light so you can see every subtle change. The speedstir light shining through the liquid actually distorts the color because it has a slight bluish/purple tinge to it. This is particularly distracting on blue-ish end points as with the CH test. I have run many thousands of TH and CH tests over the years, and I firmly believe this based on my experience. Learn how to really see and judge the endpoint before you use the light under the sample. The only time I use it is to run FC after dark. Otherwise it is just too distracting.
I want to second Jblizzle on not using the light. At least to start, and I strongly discourage it for new users. Reason being is that the light washes out the true endpoint colors. You can see them best with strong ambient light, particularly against a white background. In a lab setting, these types are run in a white ceramic dish, under bright light so you can see every subtle change. The speedstir light shining through the liquid actually distorts the color because it has a slight bluish/purple tinge to it. This is particularly distracting on blue-ish end points as with the CH test. I have run many thousands of TH and CH tests over the years, and I firmly believe this based on my experience. Learn how to really see and judge the endpoint before you use the light under the sample. The only time I use it is to run FC after dark. Otherwise it is just too distracting.