Occasional Strange FC Result - Ever happen to you

[Katygreys]

I test FC every night with my K2006C and SpeedStir and Sample Sizer. About once a month, I get an anomalously low FC reading that just doesn’t make sense and I “know” ain’t right. Then when I add 5 drops of “CC Juice” (sorry, have not yet memorized reagent part numbers…guilty as charged!) it turns pink (which it never does) and I end up with a couple ppm CC.

Every time this happens, and it’s not very often, I test again and get a FC more in line with my expectation and zero or near zero CC.

This ever happen to you? I can’t really explain it.

 

[mknauss]

Possibly the vial was not rinsed out well the previous time.

Be sure to clean your vials with rubbing alcohol every so often.

 

[newdude]

Also make sure to mentally move on from the test quickly. If it sits for 20 seconds sometimes it goes pink again and the 2nd time doesn't count. Either dump it immediately, or pay it no mind if you see the repeat pink.

 

[Katygreys]

Also make sure to mentally move on from the test quickly. If it sits for 20 seconds sometimes it goes pink again and the 2nd time doesn't count. Either dump it immediately, or pay it no mind if you see the repeat pink.

No, this isn’t a case of the sample turning pink slowly after the test is completed. Timing and execution of the test is as always, I just randomly get a much lower FC than I should and much higher CC than I should.

I honestly don’t think it’s a non-clean vial, but I’ll periodically clean with alcohol as per mknauss advice. Maybe I just grab a “dirty” sample of water once in a while (is that even make sense?). Who knows. It doesn’t happen often, and when it does I simply repeat the test with a new sample and get results more in line with what they should be. Just seems like I get an anomalous test once in a while and I can’t discern anything that I do differently.

 

[Toxophilite]

Sounds a bit like bottle switch, grabbing the wrong bottle in sequence. I've done it with some of the others, so I know it's possible.

 

[Oly]

Pull the sample below the water line 18" or more. The pump should be running at least 30 minutes prior to sampling. Sample in the same general area of the pool. Rinse all test vials and samples bottles. Be sure reagent bottle tips are producing consistent full drops by holding bottle vertically with slow and steady drop formation and application.

 

[Katygreys]

Pull the sample below the water line 18" or more. The pump should be running at least 30 minutes prior to sampling. Sample in the same general area of the pool. Rinse all test vials and samples bottles. Be sure reagent bottle tips are producing consistent full drops by holding bottle vertically with slow and steady drop formation and application.

Yep I think I’m doing all that. But who knows. Ok TFTeam, no worries!!