FAS-DPD powder and replacment help

Hello,
I searched for this answer but found nothing suprisingly??...

In my Ben's Test Kit - that I got last spring. It states that if the FAS-DPD (chlorine testing powder) goes med grey or darker replace it. What is the opinion of this board regarding this? My kit stays in the air conditioned / heated basement out of the sun all year, if temps matter...

Mine is grey now (I dont remember what color it was...) it seems to work fine so far this year? Should I got to Leslies and replace it? What is a Taylor replacement for Ben's powder? The exact replacement that is.... Seems like what I did read, the other tests dont use 2 drops per Chlorine reading...so to speak, I would like to keep it simple if possible.

thanks Kevin

Kevin,
Fresh powder is a very light gray. I think it is moisture and oxygen that will eventually cause it to turn a dark gray, almost black, and clumpy. Here's a thread where I looked into this a while back.

http://www.poolforum.com/pf2/showthread.php?t=4659

I don't have the info on the replacement at my fingertips but there is info on all that in the forum dealing with the kits.

Al

The Taylor DPD powder (same stuff Leslie's sells) is an exact replacement for the DPD powder in Ben's kit. The only difference is the scoop that Ben included is larger than the Taylor scoop so with Ben's scoop you only need 1 but if you use the Taylor scoop you need 2 scoops of DPD powder.

Hello,
Thanks for the quick replys!

So unless the powder gets close to black...and then maybe/maybe not...it will fail.
How long have folks used their powder? 2-3 years?

I will look at my local Leslie for replacements and see what it costs to buy new. Thanks for clearing up the dipper size!!

thanks Kevin

Check the stuff at Leslies before your buy. The last time I looked there the stuff they had on the shelf made Al's look good. It was black as night and one big clump.

You can order the stuff direct from Taylor here.

My Leslies didnt have DPD powder, but rather it seemed like they had a DPD *liquid*? Is that correct?

It was still DPD #1 according to the bottle but the reagent # was different. They were using it to test customer water, and it seemed like they were following the procedure we use with Bens kit, except the first step was to use this DPD liquid. Im assuming thats why they dont sell the DPD powder. If such a liquid exists, Id wonder how/if it subs with bens kits. I hate to have to pay shipping on a little batch of DPD powder, but I will if I have to I guess.

-Chris

I have successfully used the same bottle of powder for 2 years, but I keep it in a cool, dark, dry cabinet. It still turned progressively darker shades of gray, but still was good (and accurate) even when it got pretty dark. I recently had to buy a new container. Ordered it at this site, arrived in about 3 days. The number on the container in Ben's kit is the Taylor number, so they're the same.


http://www.spspools-spas.com/

Janet

Quote:

---

Originally Posted by waterbear

The Taylor DPD powder (same stuff Leslie's sells) is an exact replacement for the DPD powder in Ben's kit. The only difference is the scoop that Ben included is larger than the Taylor scoop so with Ben's scoop you only need 1 but if you use the Taylor scoop you need 2 scoops of DPD powder.

---

Waterbear: I recently ran out of Bens FAS-DPD powder and was able to purchase the Taylor R-0870 at a local pool store. The package didn't have directions, and I'd never heard that you needed two scoops of the Taylor DPD, other than I noticed the small size of the scoop. I noticed Bens powder was different - it was a mixture of powder (tiny tiny crystals) but also had noticeable crystals. The R-0870 was all powder. Anyway, I continued to use 1 scoop with the R-0870 until I read your post and ran out to my hot tub to check it. I tried with one and two scoops and got the same results...??

Why did these powders look different?

Bens original instructions were to add DPD powder until the water turned pink. He said it could take one or two scoops. I dont think it went on to say you had to do anything with the resulting drop counts (i.e. if you used 2 scoops, did you need to take half the count of drops you used). I also dont know if how many scoops of DPD you use is related in any way to the amount of CL in your water....Ive had FC down to .5 and still only needed one scoop of DPD to get the water pink.

That might be why you noticed no difference......if the water turned pink on the first scoop, you were probably good to go.

-Chris

I agree with what Chris said. It seems to make little difference in the test regardless of the powder quantity. In the TF test kit, you use one heaping spoon....it's the smaller Taylor spoon so I just sorta' compromised between Ben's one giant spoon or Taylor's two tiny spoons.

The color of the powder seems directly related to age and moisture exposure. When I get the Taylor 1 lb packs, it is a very, very, very light gray (almost white) and the smooth consistency of granulated sugar. My older powder that I've had for four years now is quite distinctively dark gray and clumpy. The best thing is I detect absolutely no difference in the performance or test results of either. I have done them side by side with identical results.

I bought a bunch of bulk reagents from the SPS place a few years ago. I keep them in the fridge and only open to refill the smaller vials used day-to-day. I used to have a color photo lab as a hobby and the developing chemicals were a heck of a lot more sensitive than the pool reagents and using the same storage techniques the color stuff lasted indefinitely. Way past the recommended shelf life. And, the test was color comparison after developing/printing, new to old chemicals. Same with color paper and films.
Al