What Does This Mean?

[rocky]

I did the Chlorine Drop Test at 8 AM this morning and got questionable readings. After adding the R-0871 powder to the test water the solution did NOT turn pink. It stayed clear. I thought maybe the R-0871 powder was old so I tried some I had recently purchased. Same results-- clear. What is going on? What is my FC? I thought I would then try to measure the CC. I added the 5 drops of R-0003 and the water turned slightly pink. Two drops of the R-0871 caused the water to turn clear. Will someone please explain these test results.

The pool is covered with a solar blanket and has not been used in several weeks. I removed the blanket and there is no visible algae anywhere in the pool. Water temperature is 80 degrees. I last did the Chlorine drop test on 21 Sep and the FC was 7 ppm. We have had in excess of 5 inches of rain the past week.

 

[Bama Rambler]

Sounds like you have zero FC and 1ppm CC. Even though you don't see it I'm betting you have a bloom starting. Get some chlorine in there quickly.

Losing 7ppm in 4 days islosing less than 2ppm/day which is perfectly normal. Why did you go 4 days without checking your FC?

Please post a full set of numbers.

 

[rocky]

I thought the FC must be 0 so I went ahead and added 364 ounces of bleach. According to the pool calculator this should get me in the 8 ppm range. I will do a retest tomorrow.

Regarding your question on why I waited 4 days without checking the FC. As I wrote, the FC was
7 on 21 Sep and
7 on 15 Sep and
9 on 11 Sep.

4 days without checking seemed ok since the solar blanket keeps the sunlight from getting directly to the water.

A full set of numbers are not currently available. However, tomorrow morning when I do the retest I will then get FC, CC, TA, pH and cya.

 

[frustratedpoolmom]

All the rain probably introduced some organics so the chlorine was used up quicker.