Note: This is my first ever post to any forum on this website.
We have had our pool for 2 years and I have only shocked it twice in that time period. I'm not even sure I needed to. However, I hear other people that shock quite frequently (every couple of weeks) and I wonder if I should be shocking it more. My recent test results for the past week are shown below:
TF100 Test Kit
Date FC CC Ph TA CH CYA
6/23/12 3.0 0.0 7.2 90 380 40 Pool store test
6/24/12 3.5 0.0 7.2 80
6/25/12 4.5 0.5 7.3 110
6/27/12 2.5 0.5 7.3 100
6/30/12 4.5 0.0 7.3 95
I measure the chemicals at least once a week, sometimes more. Over the 24 months we have had the pool I have taken measurements 160+ times. Some additional statistics for all measurements over 24 months are below:
FC CC Ph TA CH CYA
Median 3 0.0 7.6 100 325 50
Average 3.6 0.14 7.55 102 327 60 (Note: I only measure CH and CYA on average once per month)
As you can see, my numbers have been very good. I have never had a CC level above 0.5 and most often it is 0. FC generally hovers around 3. With the exception of 1 week earlier this spring, the water has been sparkling. When my chlorine gets a bit low and CC goes up to 0.5, I add some Cl tabs and CC's quickly go back to 0.
So, with numbers like these, why would I need to shock the pool? What criteria do I use to decide if shocking is required if the water is sparkling? I don't just want to do it for the sake of doing it or do it just because that is what everyone else does. I do get some algae forming on the sides of the pool and spa during the very hot summer months, but I have that problem even when FC is 3 or more and CC is 0. In our Houston climate it is tough to eliminate algae entirely and nobody said I would never have to brush the pool.
Thanks in advance for your comments / suggestions.