- Nov 15, 2018
- 188
- Pool Size
- 19000
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- Monarch ESC24 / ESC7000
G'day all,
I find myself going through far more DPD powder than is probably reasonable when doing the FAS titration.
My FC level is always so high I use a 5ml sample for 1ppm/drop, but I've still been using a heaped scoop of DPD powder.
A couple of days ago I thought I'd run a couple of tests to see how little powder I can get away with and I want to make sure I have my understanding straight.
The DPD powder is a buffer and the DPD indicator. So, provided there is enough powder there to adequately buffer the ph and turn it pink then that'll be enough? Right?
I did a couple of tests, and using a 5ml sample I can get down to ~1/4 of a scoop and still get a reliable result (ie it's the same result as doing the same test with the same water qty and a heaped scoop).
Am I right in thinking the DPD is being used as an indicator in this reaction? It's not like the borate mannitol test where you need enough mannitol to completely react with the borate.
I find myself going through far more DPD powder than is probably reasonable when doing the FAS titration.
My FC level is always so high I use a 5ml sample for 1ppm/drop, but I've still been using a heaped scoop of DPD powder.
A couple of days ago I thought I'd run a couple of tests to see how little powder I can get away with and I want to make sure I have my understanding straight.
The DPD powder is a buffer and the DPD indicator. So, provided there is enough powder there to adequately buffer the ph and turn it pink then that'll be enough? Right?
I did a couple of tests, and using a 5ml sample I can get down to ~1/4 of a scoop and still get a reliable result (ie it's the same result as doing the same test with the same water qty and a heaped scoop).
Am I right in thinking the DPD is being used as an indicator in this reaction? It's not like the borate mannitol test where you need enough mannitol to completely react with the borate.