*be prepared to fight dirty. Poolstored will if he needs to. He says "take one away' like he'd let them go. But he will not let them go. I promise you. 
FAS-DPD consistently measuring high - continuously present minor algae growth
- Thread starter PoolPage
- Start date
- May 23, 2015
- 25,695
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Part of the problem with the DPD1/DPD2 color matching is that the #2 reagent can spoil very easily and cause false low results. The test is also only good to 10ppm FC - anything over that and you can bleach out the DPD causing a low reading.
Never compare against pool store tests, they are almost always wrong even when they match a result you have (broken clocks being right twice a day and all ..).
The titration test that uses the powdered DPD reagent is the most accurate and, when paired with a SpeedStir, you eliminate a lot of uncertainty. Due the nature of the DPD chemistry, the standard titration test should be performed in under one minute. If you spend a lot of time hand swirling and waiting, you can also cause false high readings with the test.
Never compare against pool store tests, they are almost always wrong even when they match a result you have (broken clocks being right twice a day and all ..).
The titration test that uses the powdered DPD reagent is the most accurate and, when paired with a SpeedStir, you eliminate a lot of uncertainty. Due the nature of the DPD chemistry, the standard titration test should be performed in under one minute. If you spend a lot of time hand swirling and waiting, you can also cause false high readings with the test.
cwswifty
Well-known member
- Sep 14, 2023
- 259
- Pool Size
- 26500
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Jandy Aquapure 1400
- Jun 1, 2018
- 16,012
- Pool Size
- 26000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
Not swap the reagents to another bottle - swap the tips of the bottle.
Defective tips do happen occasionally.
As for the too many drops thing. It should be a drop per second- I do a rythmic count. It becomes second nature.
I was a manual stirrer (a swirler) for many years and personally it was no trouble for me, but some have issues with it as they do the drops (pausing and such). You kinda gotta be good at the pat the head rub the tummy thing lol
I was blessed with a magnetic stirrer and it is great
one less thing to have to focus on. The built in light is also chef’s kiss 
makes the end point of the tests extremely obvious. Truly my favorite part.