Quote Originally Posted by psciotti View Post
Would any of these issues have any affect on pool chemistry:
Yes.

+ The compressor could add oil to the pool. If have a heater bypass, open it and close the pipes to the heater.
+ Sand doesn't 'wear out' but it can clump up. Most often, however, it gets blown out of the backwash by mismatched pumps, and needs to be replenished. You should check it, after 9 years.
+ With your pH levels, it would add LOTS of copper. Remove the cartridge . . . and don't buy another one.