Cooper seems low, but can cause problems after many topoffs... Nutrients are stacking when topping-off.
One of my LFS
use tap water (with prime) for their WC
, they don't seems to have significants coral problems... On the other side, they have a lot of GHA in the tanks.
is using tap water, doing waterchanges each 3 weeks, but thoses tanks are no more reefs, I will more call this Algae tanks.
Another store, (reef solution), is using his homemade high quality saltwater (from RODI
), and there's no traces of algae in their tanks, and corals are healty.