Thanks to Jason and the contributors for an excellent site. Within 20 mins of registering, I quickly diagnosed my pool's issue(s) and am on my way to headache-free ownership.
A little background. I bought my current home in Dec-2002 and had never owned a pool before. Not only is this my first pool, its also a BFP (Big Freekin' Pool) for backyard installations...... 16' x 48' with a 9.5' deep end. Total water volume: 45,000 gallons. The pool was installed ~1979 and was made large to accommodate the then-owner's hatred of yard care..... Not the best logic, but I guess it worked for them.
I must admit that I tested the water "intermittently" at best. and the results were obvious. Every summer I had a few "good" days when the water would go into remission* and look OK.... Mostly I fought algae cloudy water.
Well....... Fast forward the movie 2009. This year I decided to get ahead of my pool and get it ready for prime time. I bought a DPD test kit and began to test away.
Water condition: Algae on all surfaces and water was crystal clear.
Yep... The CH and CYA were off the scale. No wonder since I had been shocking with Power Power Plus over the years
I must admit I was brainwashed since I worked at the "L" store in high-school so please don't hold that against me.
After reading about the BBB method and harking back to my high-school chemistry, it all became clear that the BBB method should work..... Even for a BFP.
Suffice it to say, I had to drain the pool (last week) and start over with fresh water. While drained, I fixed some rough spots in the aging plaster and had the pump seals replaced. As I type, I am re-filling the pool and will use the startup method in Pool School.
I will post results as they come in.
Thanks again for the depth of info here!
* Remission from algae attack