DPD Powder

[tclproductions]

So I have probably done 15 tests and I am getting low on DPD powder - it says its good for about 100 tests. I am using 1 heaping blue spoon full. But there is no way I can get 100 tests out of that little amount of powder. Am I using too much?

 

[JoyfulNoise]

Which kit are you using? Are you using the little blue scoop that comes with the powder bottle? What water sample volume are you using, 10mL or 25mL?

 

[tclproductions]

Which kit are you using? Are you using the little blue scoop that comes with the powder bottle? What water sample volume are you using, 10mL or 25mL?

little blue scoop - 10ml

 

[JoyfulNoise]

Then all you should be using is one scoop of powder that fills up the little 0.05mg indentation in the spoon. It's ok to use a slightly rounded fill, but it should only fill that little indentation. If you are using a heaping scoop, it's too much.

 

[Saturn94]

Interesting to note the instructions for the TFTest kit calls for a heaping spoonful (10ml sample).

Personally I use a slightly rounded spoonful.

 

[JoyfulNoise]

The adjective "heaping" is totally unnecessary. One simple scoop of powder is roughly 0.05mg by weight. In a 10mL water sample, there is more than enough DPD indicator dye to fully react with 10ppm FC (and even a little more than that).

Using a slightly rounded & full scoop of powder is all that is needed unless one expects to have more than 10ppm FC in which case one can use 2 scoops.

 

[Saturn94]

The adjective "heaping" is totally unnecessary. One simple scoop of powder is roughly 0.05mg by weight. In a 10mL water sample, there is more than enough DPD indicator dye to fully react with 10ppm FC (and even a little more than that).

Using a slightly rounded & full scoop of powder is all that is needed unless one expects to have more than 10ppm FC in which case one can use 2 scoops.

Great info.

 

[tclproductions]

Great info.

Yes, great!! Thanks!!

 

[camueller]

The taylor kit says to add 2 scoops (presumably no matter the sample size), so I've always wondered. Also, crud builds up on my scoop, so I always worry it isn't able to hold the proper capacity. I guess I should rinse it off each time.

 

[JoyfulNoise]

The taylor kit says to add 2 scoops (presumably no matter the sample size), so I've always wondered. Also, crud builds up on my scoop, so I always worry it isn't able to hold the proper capacity. I guess I should rinse it off each time.

Simply rinsing the dipper under tap water for a few seconds and drying it with a paper towel will keep it clean and free of build up.

Using two scoops of R-0870 ensures that there is excess DPD to cover the full range of the test. Under normal water conditions (FC < 10ppm), 1 scoop of R-0870 in a 10mL water sample is more than enough.