Opened my pool last weekend to a green swamp (bought the house this winter so I had no control over the pool closing).
I've been shocking the pool ever since, per instructions in pool school. I use the pool calculator and test with a TF100. Ok, all good so far.
What is puzzling me is that when I test in the morning, CC are at or near 0, but by the end of the day they skyrocket. What causes that? Is the daylight sun helping the chlorine battle the nasties? Where does the CC go overnight? I suspect I may have an ammonia problem (haven't tested) because CYA was 0 at opening and the pool was filled with crud that I have done my best to remove.
Here is my test history:
@ pool opening last Saturday (May 18)
So I immediately started shocking (bleach) as well as adding enough CYA to get to 20 ppm.
Yesterday is a good example of what I'm talking about. At 7 AM I tested and found FC=9 and CC=1.5. So I added a enough bleach to get back up to shock level (11). I was out all day working the polls (election day) and didn't get back until 11 pm and found FC=2 and CC=7. Dumped enough chlorine to get back to shock level. This morning, at 7:30am I tested and got FC=13 (oops, overshot) and CC=0!
My pool gets full sun all day long. I still have a bit of fine debris on the floor of the pool. I can see the bottom of the pool and the water is clearing slowly.
Anyone have any idea what is going on with the FC/CC levels? I understand I might be losing FC during the day to the sun, but I'm not losing much at all at night. And why does CC skyrocket during the day and plummet at night?