Speed Stir Usage question

tgrinchy

Silver Supporter
Aug 13, 2019
15
Houston
Hi Everyone! I have my TF-100 kit and practicing the art of testing my water - had a question regarding using the Speed Stir. As I do each test, should I drop in the reagents and then turn on the speed stir to mix, or can/should we have the speedstir on (mixing) while we're adding in the various reagents?
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
16,945
Tucson, AZ
Measure out water sample size WITHOUT the magnetic stir bar.

Drop in magnetic stir bar and turn on speedstir.

Add reagents and titrate as directed by the test procedure.

Rinse out test tube and stir bar.
 

tgrinchy

Silver Supporter
Aug 13, 2019
15
Houston
Thanks everyone! Quick question on the TA test - when I did it, I saw the color change to red and back to clear - then eventually stayed red the more reagent I add.

Do I stop when I see it just change red or do I keep going to when it turns red and stays red?
 

ckendalls

Gold Supporter
May 17, 2018
61
Clermont FL
Thanks everyone! Quick question on the TA test - when I did it, I saw the color change to red and back to clear - then eventually stayed red the more reagent I add.

Do I stop when I see it just change red or do I keep going to when it turns red and stays red?
The latter. You read the number or drops it takes to stop changing color. It may change to lighter red first and with another drop go brighter red. Use that number. Also, with new kits and particularly in dryer weather, static electricity on the tip of the R-009 reagent can affect accuracy so you might try wiping the tip between drops to see if that affects results.
 
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