Stain (?) Help

[zbest]

Please bear with me as I am new to this .

I recently noticed a discoloration mainly on the spa seat and floor. Not sure what it might be. Pictures are attached (disregard crosshatch pattern as it is a shadow from the pool enclosure overhead).
Pool chemistry is checked weekly at local pool store. Most recent readings on 5/31/16:

TC 5.0
FC 5.0
PH 8.0 (MA added to reduce it)
TA 100
CH 225
STABILIZER 60
TDS 4,500
SALT 3,000 (salt added)

Sorry for the quality of the photos, but it is shooting through the water naturally. Ty.

 

[pooldv]

Welcome to TFP!

Read this and tell us what you think. We can go from there.
Diagnosing Pool Plaster Problems

 

[zbest]

I read the thread and found it fascinating.   That being said, I really don't know how to proceed at this point.  Leave it as is if,indeed it is only a cosmetic issue though my wife may not approve.  Or call in a plaster company to have a look.    Do you have a recommendation on a way forward?

 

[pooldv]

Are the stains rough to the touch? Do you think it is calcium scale based on the description? Your high PH and TA are indicative of potential for scaling. This is new this year? How old is the pool?

 

[JamesW]

It might be copper. Is the turquoise hue the original color of the plaster?