I just opened about 2 weeks ago. I've run the vac several times, brushed the walls and run the sand filter 24/7. Here are the numbers (18'x36' 23,000 IG vinyl pool):
The water temp is 60 and the pool is crystal clear. Here's the problem: I've been losing chlorine at a rate of about 10 ppm per day. The air temperature hit 75 today, but has been in the high 60's for the last week or so. I've been trying to keep the chlorine at around shock level (25-27 ppm) until the cl holds overnight. Here are the cl numbers from the last 24 hours:
yesterday 8 pm: 23.5
today 4:30 AM: 23.0
2:30 pm 20
5:00 pm 18
6:00 pm 16.5
I thought I was out of the woods when I saw the cl remain fairly constant over night. But then I lost 7 ppm before the sun went down today. In the past, a 2-4ppm drop was normal--higher if we were in the pool all day. 7ppm is a big drop for a cool day, cold water and a bather load of 0. I hate to think how much I'll be using when it's sunny, 85 and full of 9 year old kids with questionable potty habits.
I just added 4 jugs of 6% bleach which will kick the cl back up to around 25. Should I stay there or go even higher? Again, the water looks perfect (I can tell the main drains are fastened down with a philips head screw!). Am I missing anything obvious? Got any suggestions?
One other thing--does the cooler water temperature effect the reliability of the cl test? Should I be warming the water sample up before I test it?