I have been doing the FAS/DPD test using the Taylor Speed Stir since I got my TF100 kit. Last night I was testing and I noticed once I was done testing and removed the cylinder from the speed stir, it was pink again (this is not due to the few minutes of sitting that the waster will turn pink). I think with white stir pill taking up so much room in the 10ml of water, the spinning white seems to dilute the pink and appear clear before it actually is clear. Has anyone else noticed this or am I just not sensitive enough to detecting the change in color? I repeated the test a few times with letting the speed stir get the water pink, then I took it off and added the 871 reagent as I swirled by hand....I got about 2ppm higher reading. Just wondering if anyone else out there has experienced this...I'm fine adding the 871 while swirling by hand, but I figured the speed stir would give a more accurate reading....
FAS/DPD Test With Taylor Speed Stir
- Thread starter 440dodge440
- Start date
Once you get clear the last drop you put in is your FC once multiplied by .5
When it sits it will turn pink again. Just ignore it.
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The speed stir does give you more accurate mixing.
When it sits it will turn pink again. Just ignore it.
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The speed stir does give you more accurate mixing.
The last drop is when all color is gone. As soon as that happens, you should add five drops of R-0003 for the CC portion of the test.
I was doing the testing as it was getting dark, so I had the speed stir light was on, so that may have been part of it...I'll have to repeat the testing earlier with more daylight. It just shocked me with the difference in FC measurement
So it's not just me...I don't want to stop using the speed stir, but I do want to track down my problem- maybe the light is it....
Thanks
Thanks
jcowart
0
I use the light but look through the test tube. I miss the transition if I look down in the tube while testing.