When I’m testing for calcium hardness, the water turns more a light pinkish than red when I add the drops R 0010 and R 0011. Then when I add R 0012 instead of turning blue, The water turns clear. Maybe it has a very faint bluish tint or maybe I’m imagining it. Is this still a valid test or is this an issue with one of the reagents? Or could it mean something else? Thanks. While the reagents are admittedly, a year old now, they’ve been behaving this way even when they were brand new.
TF 100 calcium hardness question
- Thread starter Jim H
- Start date
- Jun 1, 2018
- 16,080
- Pool Size
- 26000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
Follow these extended directions & see how you fare
www.troublefreepool.com
Calcium Hardness
A drop-based test that measures the hardness in your water. Once measured, it is used … Read more…
www.troublefreepool.com
- Jul 21, 2013
- 65,634
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
- Jul 21, 2013
- 65,634
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Beware the Fading Endpoint
Occasionally when testing calcium hardness you may get a purple endpoint instead of blue. This is called a "fading endpoint" and is due to interference from metal ions (most likely copper from algaecides, pipes, or source water). Retest, but prevent the interference by adding five or six drops of hardness reagent to the sample before adding the buffer and indicator. Then proceed as usual. Remember to count the drops of titrant added at the beginning when you calculate the total number of drops required to reach the endpoint.I went for the more precise method of adding 25 mL of pool water. The water was still more pink than red but slightly darker and it changed at the same levels as when I did it the routine way. The water is definitely blue If you look closely it’s just a very, very faded blue I think part of the problem was I was using the light on my magnetic stirrer and it sort of drowned it out the blue color when I turned the light off it’s more obvious. I don’t know why a few years ago when I did this test I remember the blue being more obvious. It’s very very light, but it is definitely blue and since I got the same number doing the routine way and the 25 mL way I’m just gonna go with it. Thanks for your help!Follow these extended directions & see how you fare
Calcium Hardness
A drop-based test that measures the hardness in your water. Once measured, it is used … Read more…
Most all the drops based tests are based on a color CHANGE rather than a particular hue. It is the CHANGE in color of the sample rather than the intensity thyat determines the endpoint