First time pool owner questions on filter and pop-up floor cleaners

[bpuck]

This pool also has a heater if that might be where the copper is coming from?

[PoolDoc]

Very possibly.

And, if it is, you'll need to plan for a heater replacement (or possibly, a heat exchanger, if the heater is new) in the near future. You may have quite a bit of damage.

Low pH is the cause of this sort of damage. Often, there may be tabs in the skimmer or a tab feeder in FRONT (water flow wise) of the heater, instead of after it.