Inconsistent FAS-DPD Test

[ewkearns]

I would suggest you leave the bottle inverted over the sample tube and just keep the drops dripping out. You should not be inverting & righting the dropper bottle during the testing.

Agreed. Each drop should have a bit of "linger time," before dropping.

If you can't get to that level, then you should purchase a SpeedStir as that will free you from having to swirl the test solution.

Worth its weight in gold.

Too often folks try to "save" powder by only using one scoop. While I understand the reagents are expensive and they take time to ship, using less than the required amount of powder can lead to measurement error.

IMHO, this is a bit of "penny wise and pound foolish" married to clever purchasing. Currently, at 3 ppm chlorine, it costs me:

(Group 1)
4.7¢ for a FC and CC test combined (25 mL),
.9¢ for a pH test; plus 1.5¢ if I use the demand reagent.

my daily testing costs 5.6¢- 7.1¢ per test.

(Group 2)
TA costs 2.7¢ per test
CH costs 10.3¢ per test
CYA costs 22¢ per test.

my once-a-week test expenditure is 35¢ and,

(Group 3)
CYA costs 22¢ per test.

my once a month testing costs 22¢

So, testing monthly, costs me (Group 1) [twice daily] $3.36; (Group 2) 4 times per month $1.40; (Group 3) 22¢ per month --- yielding a monthly outlay of $4.98.

Compare that amount to [Your Guess] bottles of bleach at [your cost] to SLAM and......

In fact, I actually use the Taylor Unit-Dose Dispenser for my R-0870 powder which dispenses a little bit more than two full dippers worth of powder. Do I use more powder than average, sure. Do I ever get inconsistent test results ... not yet.

Branded a "geek toy' by some here, I find that this keeps my R-0870 from being clumpy and gives consistency in metering. I highly recommend.

 

[ThomasG]

Today's Results:

2 level scoops, bottle vertical and upside down the entire time
7.5
Retest
7.0
Using a speed stir and have been for awhile.

The R-0871 drops from the TF Test Kits large bottle (about 1/4 full) required a slight squeeze to release them during the first test. For the retest, the first 5 drops fell out of the bottle with no squeezing. the 0.5 difference seems to be within the margin of error for the test.

 

[JoyfulNoise]

Testing error for all Taylor titration tests is -

+/- 1 drop when drop count <= 10 drops

+/- 10% of final value for drop count > 10 drops

So yes, 7.0/7.5 ppm is with the MOE.


Sent from my iPhone using Tapatalk

 

[chem geek]

The Taylor standard for their dropper tips is 24 drops per milliliter so 5 ml is 120 drops. When you use up the reagent, save the bottle and you can test it with water in it to see if it has the right number of drops.

Also, if you aren't getting well-formed drops, wipe the dropper tip with a damp cloth to remove any static electricity. Usually it's the TA test that tends to have static on the titrating drops, but any test could get some in dry (low humidity) areas.

 

[Scoop]

The Taylor Unit-Dose Dispenser (9250) sounds interesting to me. I have a couple of questions about it after viewing the video at the Taylor site.

- Is the the Unit-Dispenser compatible with the TFT R-0870 container?



The Taylor instructional video recommends removing the Unit-Dispenser from the powder container after using it to dispense the powder to prevent the powder from being affected by moisture.

- For those that are using the Unit-Dispenser, do you normally remove the Dispenser from the power container daily?

I'm usually checking my CH levels with the powder about once every 3 days.

 

[ewkearns]

If that is the TFTestkit screw-on container, it is not compatible with the Unit-Dispenser.

I do not remove my dispenser. You could run some tape around the bottom of the dispenser to seal it. The unit is capped when not in use.

 

[JoyfulNoise]

Does not work with the TF-100 powder bottle. It's designed to snap on to the Taylor bottle.

I typically take mine off each time I use but I have left it on too. My test kit stays stored in a very cool and dry space and I live in the desert, so humidity and moisture is not really an issue for me. If you test everyday (as you should ) during the swim season, it's probably best to leave it on. If not, then I'd remove it each time.


Sent from my iPhone using Tapatalk,16k gal SWG pool (All Pentair), QuadDE100 Filter, Taylor K-2006

 

[Scoop]

If that is the TFTestkit screw-on container, it is not compatible with the Unit-Dispenser.

I do not remove my dispenser. You could run some tape around the bottom of the dispenser to seal it. The unit is capped when not in use.

Thanks for the info

Does not work with the TF-100 powder bottle. It's designed to snap on to the Taylor bottle.

I typically take mine off each time I use but I have left it on too. My test kit stays stored in a very cool and dry space and I live in the desert, so humidity and moisture is not really an issue for me. If you test everyday (as you should ) during the swim season, it's probably best to leave it on. If not, then I'd remove it each time.

Thanks .

I adjust my FC test frequency seasonally. I test every other day during the summer months in Dallas while keeping the FC level within my FC/CYA ratio range.

Currently, I'm using the "1 heaping spoon" method for the powder since I've read that several places at this forum and that's the method included in the TFT site instructions. I experimented with 2 scoops vs 1 heaping scoop when I first began using the FAS-DPD testing this past summer but didn't notice much difference in repeatability.

Since then, I just go with my 1st FAS-DPD test result using the 1 heaping scoop method.

I'm using the Taylor vial (with the SpeedStir) with the SampleSizer for all of my tests.

However after reading this thread and the Taylor recommendation of 2 scoops, I'll get the Unit-Dispenser since I like the idea, and switch over to the Taylor powder container.

 

[JoyfulNoise]

I'm using the Taylor vial (with the SpeedStir) with the SampleSizer for all of my tests.

I love all my pool nerd gear

The Unit Dose Dispenser is great. Just remember to follow the cleaning directions as the powder can and does build up in its our needs proper rinsing and cleaning with isopropyl alcohol (to displace any rinse water out of the crevices).


Sent from my iPhone using Tapatalk,16k gal SWG pool (All Pentair), QuadDE100 Filter, Taylor K-2006