DPD powder

[DavidD]

Kurt,

Yes the water is perfectly clear at the start, then I add the DPD powder, shake and the water becomes pink. Then I start adding the R-0871 and the pink goes away but the water is not as clear as it was at the start. It's not really milky it's just not clear. When I add the DPD #3 reagent to the cloudy water in the comparator the color of the water remains unchanged (no hint of pink) just the same cloudy water.

My pool is very clear. One can read the writing on the main drain covers from the jumping rock.

I appreciate you input. I guess I will continue to use the powder until either someone makes a case to do otherwise or I need to order more reagents.

Gary

So it is the water in the test vial that is cloudy. I believe this is normal. If your DPD gets a dark gray, clumpy or real grainy then those are signs it may be going bad. Don't worry and keep testing...

DAve

[Jakebear]

You only need enough DPD powder to turn the water nicely pink. Any more just wastes the powder--it doesn't turn it pinker. It seems weird, but that's how the stuff works.

I was having problems with getting any CC results using my FAS-DPD kit. When I called Taylor Technologies technical service, they told me that the amount of powder used is important.

Being a skeptic (and Cheap) I ran some tests. I ran the same sample 8 times --- 10ml 1 scoop, 10ml 2 scoops, 25 ml 1 scoop and 25ml 2 scoops. The results consistently gave more accurate results (less variation) when two scoops of the powder were used. The difference was 1.8 ppm higher when using the preferred (by Taylor) method using the 25ml sample size. I did the same routine over again --- the results were repeatable!!

Thought you would want to know!!

[DavidD]

So when you say 2 scoops, what scoops are you referring too, Ben's scoop (White) or Taylor's (Blue)?

Dave

[atwetzel]

And are those level scoops, rounded scoops, heaping scoops?

[Jakebear]

Taylor scoops (blue) --- Level

Edit --- Didn't know there was more than one since Taylor makes the reagent.

[cwstnsko]

I've seen both scoops, The poolsolutions scoop is much bigger than the taylor. I've tried the 10 ml test with 1/2 and whole scoops of Ben's scoop, and the test was the same for normal levels of chlorine. If I'm measuring shock level chlorine, I make sure I get a whole scoop just to be safe

[DavidD]

Taylor scoops (blue) --- Level

That explains it, you are supposed to use 2 scoops when using the Taylor scoop. Ben, the forum moderator, puts a larger scoop in his kits (he does use Taylor DPD powder). They are twice the size of the Taylor scoop so you only need one scoop. I think he did this to make it just that much easier. Ben has really put a lot of thought into his kits. The size of the re-agents is another example. He matches volumes of re agents to the amounts required for testing with the idea that you should use both chemicals required for any given test up at or about the same time. His kit is a combination of a a coupe of the Taylor kits at a great price.

Dave