CYA > 300ppm, FC at 2-3ppm CRYSTAL CLEAR POOL!

Can someone please explain this? I use a Taylor K-2006 FAS-DPD kit to test my pool. My CYA is through the roof, using the dilution method I'm estimating my CYA is >300ppm, maybe higher. The black dot disappears with a few DROPS of water., it's that turbid. For the last 2 years the only chemicals I've added are 3 trichlor tabs weekly I'm the summer, maybe 3 tabs every few weeks in the winter (....I know, the triclor tabs are the root of the CYA problem). Maybe shock it once or twice a year with a pound of shock. My FC Level rarely gets above 4ppm. But my water is CRYSTAL CLEAR, even in the 115 degree Phoenix summers. I've NEVER had algae. No cloudiness. The water has always looked pristine. Only complaint is the water tastes dull.

How is it possible that my pool stays clear with this CYA/FC ratio? The charts I've read indicate my FC should be at least 8ppm, and probably higher.

I have a 12000 gallon pool, pebble tech lining. Pentair variable speed pump/cartridge filter running at about 2500rpm 3 hours per day and 1000rpm 3 hours per day. In floor cleaning system.

I wish I knew the other chemical levels off hand to share as I'm sure it may offer clues. pH is 7.6, calcium is high.

Thanks in advance! I'm curious what you guys come up with!