Hi Ben... Thanks for your quick reply and help. Below are the answers to your questions:

1. Following pool-store instructions I added one 2.5 gallon jug of liquid CL (pool-store bought) and I bottle of algaecide bought at Walmart (sorry, I don't recall the name or size. If needed I can go back to Walmart and write them down). After running the pump for a couple of days and having no change, I repeated the above treatment.

2. Sorry, don't understand what DE powder means. Can you clarify?

3. The pool was already installed a number of years before I bought the house. I couldn't find the model on the pump but it does have the metal tag with the specifications. There I was able to read that it's a 3/4 horse power pump running at 220 volts. If this is insufficient, let me know and I will try again. The cartridge filter is a Hayward C-1100.

Your other questions:

1. I was referring to the table that says what level to hold CL based on your CYA reading. I shocked at 20+ ppm for several days adding pool-store bought liquid CL (its actually cheaper than store bought bleach where I live), adding it in the evenings while running the pump and frequently cleaning the cartridge filter. Your guidance worked perfectly and I cannot see any algae anywhere in my pool.

2. Taylor K-2006. The CYA reading was my guestimate. The liquid level on the back of the tool was closer to the 40 ppm scale line than the 30 ppm line.

3. I read on the site how many pools have a natural PH level and I believe that mine may run at the higher side. I also read the discussion and rationale on running with a higher PH overall. If I misinterpreted what I read please let me know.

A couple of other items that might help and that I left out before:

1. I live in very sunny South Florida and the pool is in the sun all day. Only other thing is that it has an enclosure around it (with a fine mesh) but this is mostly to keep out the bugs.

2. I have an automatic pool cleaner (Baracuda) so when I run the pump it is drawing from the bottom of the pool and not the surface thru the skimmer.

Thanks again for your help and patience.