Chlorine Only cylinder

[elainerader]

I have been using my testing kit now for three seasons. I was slamming the pool last month and testing with new chemicals purchased mid season last year.

While testing with the DPD powder, my chlorine only cylinder and the Taylor Speed stir, I noticed that there is a black deposit on the cylinder and the magnet of the speed stir that will not come off. I wash and dry them both after each test.

I just ordered new DPD powder, R-00871 and a new cylinder, but I was curious if anyone had the same experience with the black residue? Bad chemicals or what??

Thanks.

 

[poolnoob.ca]

Hi Elaine, have never seen any reference to the black residue, but i found in the extended test kit directions how to clean the cylinder:

Over time, it is common for a cloudy residue to build up on sample tubes used for FAS-DPD chlorine testing. The residue can be removed by filling the sample tube with bleach, letting it sit for several minutes, rinsing, and then wiping throughly with a paper towel.

 

[jhkh]

I have been having the same problem with my cylinder & powder from last year! I read through another thread that recommended filling the cylinder with bleach, let it soak for a few minutes, then rinse with water & dry with a paper towel. It worked, but the staining (mine looks really dark purple/black & so is my powder) came right back. I'm thinking I need new powder & cylinder too. I'm curious what others say too.

 

[Scuba_Steve]

I have had my kit for only a couple weeks and I already have the black stain...???

 

[mikech]

I had this recently, got new powder with no issues. A couple of drops of MA in the cylinder with water cleaned it right up.

 

[mikech]

One tip might be to put a few packets of silica gel in your test kit box. My powder went really black and clumpy when I left my box outside for a few days in the FL humidity.

 

[chiefwej]

Rinsing after each test seems to prevent any buildup. I just use some of the pool water from the squirt bottle I use to collect my sample.

 

[Patrick_B]

Always rinse your glassware. Standard OP's for lab testing. In this case it will help, but not eliminate this.

 

[elainerader]

One tip might be to put a few packets of silica gel in your test kit box. My powder went really black and clumpy when I left my box outside for a few days in the FL humidity.

My kit is always inside in A/C in a drawer....????

- - - Updated - - -

Yes I think the thing to do is get new stuff! I'll post gain when I get my chemicals and new cylinder.

I have been having the same problem with my cylinder & powder from last year! I read through another thread that recommended filling the cylinder with bleach, let it soak for a few minutes, then rinse with water & dry with a paper towel. It worked, but the staining (mine looks really dark purple/black & so is my powder) came right back. I'm thinking I need new powder & cylinder too. I'm curious what others say too.

- - - Updated - - -

Thanks everyone for your feed back! I'll post again when I get my new stuff and see if there is any difference.

 

[Patrick_B]

I seriously doubt there is any issue with this reagent. The darkening just happens. Better if you rinse and clean well after testing, but it's not a big deal.

 

[mikech]

Nope. When my powder went 'bad', if I added and swirled I would end up with very 'sticky' black/purple spots on the cylinder. Even pool water or bleach based cleaners wouldn't touch them. MA did the trick though! Ok, I'll rephrase bad as the FC test still worked as expected, just a pain to get rid of the spots each time.

 

[Scuba_Steve]

I still would like to know how I am having this issue?

Kit is only 2 weeks old. I rinse every time repeatedly. Then I turn the tube upside down to finish drying and leave it that way until next test.

My powder is not black btw.

 

[chiefwej]

Considering how fast things dry where I live, drying the test cylinder shouldn't be a problem. When I store my kit I always inserted the container of powder in the top of the test cylinder. The last time I did that, I guess I didn't rinse it well and wait for it to be dry. When I got it out it had a very dark cloudy area on it, where the water had dried. With just a bit of rinsing and rubbing with a paper towel it came off though. I'm guessing that is what you are seeing.