FC/CC Test Question

[Deb04]

I've never had this before. When I do the FC test, the sample goes clear for less than a second and then gets light pink again. Do I add more R-0870 or move on to the CC test?

My current numbers are

FC 10 (stopping at flash of clear)
CC 1.5 (doing CC test starting with light pink before adding R-0003)
pH 7.5 (done yesterday before FC was raised > 10)
TA 70
CH 270
CYA 40-50
Salt 3250

FC was raised because I wasn't feeling well yesterday and husband took over and added more bleach than I wanted him to. We hadn't turned on the SWG yet because we just got the salt up high enough today.

 

[Richard320]

If it's just a flash, keep testing. You want it to go clear and stay that way for at least long enough to grab the R-003 and uncap it. I use a speedstir, so I haven't seen that in a while.

But don't forget, if it turns clear and you set it aside to do something else and a minute later you notice it's pink again, ignore it. That doesn't mean anything.

 

[Deb04]

Ok, thanks. It is just a flash. Will retest.

 

[JoyfulNoise]

The DPD-FAS test can bleach out if you have high FC and don't add enough powder. What you describe could be not enough DPD powder to react with all of the chlorine. What water sample size were you using and how much powder did you add? I would suggest that you perform the test again but make sure you add two rounded scoops of powder. One way to know if you've added enough is if you see a small number of tiny, undissolved crystals in the solution. That is ok and perfectly normal.

 

[duraleigh]

What you describe could be not enough DPD powder to react with all of the chlorine.

+ one to that. I suspect your FC is quite high and you will need two scoops to get the (pool water + R-0870) solution to retain the pink color.

 

[Deb04]

I retested and my FC was 12 and CC was 0.

Tested today and FC was 10 and CC was 0.

Feeling happy.