Plaster colors darker than white are never completely even, i.e. there is always some mottling. Your color variation is about what I would expect, though the pattern of the variation is more unsightly than normal.
Yours looks a lot like mine--especially the roundish splotches. I've heard that a no-drain acid wash might help, but it reduces the life of the plaster. I just live with it. It's only really noticeable in low light. When the sun is out it looks fine. And I don't believe you have calcium scale. This is the condition that Onbalance has written about.
9,200 gal. Gunite Luna Quartz French Grey pool with spill over spa, two fountains on tanning ledge (rarely used)
Pentair Whisperflo 2HP, Pentair CCP Cartridge 420 Sq. Ft., Polaris 280 with booster pump
Pentair EasyTouch 4, RayPak LoNox 266k Natural Gas heater, Aqua Rite SWCG T Cell 9, Borates, TF-100 test kit
I just came across this post today.
The mottling and white spotting in your pool is not normal.
See this post for further information: http://www.troublefreepool.com/threa...-Plaster-Pools
This problem is also why your calcium level is increasing rapidly.