Increase in FC without adding chlorine

[pool$123]

I recently opened my pool and did not have to add any liquid bleach as the levels were still near slam level. I tested FC yesterday and it was 8, however, after testing it today it is at 15? My CYA is 30-40 and there is no CC. PH is 7.4 and TA is 80. What would cause this increase?

 

[AimeeH]

What test kit are you using? Do you have a SWG???

 

[duraleigh]

What would cause this increase?

Testing error or someone put chlorine in the pool. No other possibilities.

 

[pool$123]

Test kit is k-2006. Not sure what you mean by SWG but I think you are referring to the filter.....it is not a sand filter but a cartridge filter.

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I tested it twice today and results both times were 15.

 

[YippeeSkippy]

SWG=Salt Water Chlorine Generator

 

[pool$123]

Not SWG on our pool

 

[Richard320]

Is there an inline Chlorine feeder with pucks in it? Or did someone get helpful and drop a few in the skimmer?

Chlorine's coming from somewhere. Or you're testing wrong. Any chance you're using the wrong factor to multiply drops?

10 ml sample, 1 drop is .5
25 ml sample, 1 drop is .2

 

[pool$123]

you know what......maybe I used the 25ml mark.........multiplying 30 by .2 gives me FC of 6, which is more in line with my tests over the last few days. How many scoops of the white powder (0871 I think) should I add to my pool water to test for FC. I have been adding 2 scoops.

 

[Richard320]

you know what......maybe I used the 25ml mark.........multiplying 30 by .2 gives me FC of 6, which is more in line with my tests over the last few days. How many scoops of the white powder (0871 I think) should I add to my pool water to test for FC. I have been adding 2 scoops.

Usually one is enough. After swirling it to dissolve it, you should see a couple undissolved crystals. If you do, it's enough. Somehow they dissolve when you add drops.