Can save titrant with a gallon of distilled water for dilution too, not to mention extend the testing range
I looked at trying that for the PH using a spreadsheet, it's not workable (but your welcome to try).
Old claggy DPD powder
- Thread starter Brad_C
- Start date
Can save titrant with a gallon of distilled water for dilution too, not to mention extend the testing range
I looked at trying that for the PH using a spreadsheet, it's not workable (but your welcome to try).
- Nov 15, 2018
- 188
- Pool Size
- 19000
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- Monarch ESC24 / ESC7000
I’m sorry, I don’t understand that at all. Are you suggesting I dilute the water sample for the chlorine test rather than just use a 5ml sample?Can save titrant with a gallon of distilled water for dilution too, not to mention extend the testing range
I looked at trying that for the PH using a spreadsheet, it's not workable (but your welcome to try).
Yes, for instance, half sample and half distilled water, reading will be half, drops used will be half, and you double the reading to get the true number.
One time I wanted to read a lower value of CYA, so set the sample in the sun until half evaporated. Testing and doubling the result moved the number back on scale.
I suppose doing the same, setting out a sample until FC depleted, would insure accurate PH test results if you were concerned the test would be inaccurate due to high CHL in the sample, but I've got a hot tub so this situation doesn't apply to me (yet)...
I wonder if you can "recharge" the desiccant in a used up DPD bottle so you could move some to it from a new one ... just to keep from having to expose all the new powder every time the container is opened?
edit: For concern over using up supplies, I find that I don't need two scoops of the powder. About 3/4 of one scope reads exactly the same, at least at the ranges I keep testing.
- Mar 5, 2020
- 3,018
- Pool Size
- 66000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Astral Viron V35
There is no need for the dilution. Just use a 5ml sample. In the end it's about the total number of molecules to be tested for in that sample. Whether you than add more water molecules doesn't change the titration result.
In the same way that you don't have to fill up a 10ml sample to 25ml to make the test with 0.5ppm per drop.
Dilution helps to a certain degree for pH testing with FC above 10ppm. The dilution reduces the FC concentration, which is what matters for the pH test interference, but has only a small impact on pH, as the distilled water is pretty much unbuffered, but the pool water sample is buffered.
- Mar 5, 2020
- 3,018
- Pool Size
- 66000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Astral Viron V35
I know. The point is, you just take a 5ml sample to do the test with 1ppm/drop resolution, you don't have to fill up the 5ml sample with distilled water to 10ml. You don't need dilution, just a smaller sample size. To then stretch the smaller sample to 10ml is just a waste of distilled water and time.
25ml sample: 0.2ppm/drop
10ml sample: 0.5ppm/drop
5ml sample: 1ppm/drop
Last edited:
- Nov 15, 2018
- 188
- Pool Size
- 19000
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- Monarch ESC24 / ESC7000
Precisely. I use a graduated pipette. As a bonus it’s ~12” long, so I can put it into the water to fill and get the water from a foot under the surface, then get a precise sample size without getting wet. Diluting it would just be a waste of time and water.
As for pH, I use a decent meter, so CL is irrelevant.