We longingly looked at these scuppers for sheer descents which our PB mentioned: Bobe Water & Fire Features

The prices were out of our budget since we had already gone over on so many other materials. We ended up with simple invisible sheer descents although I think we did upgrade to the larger size. I don't recall whether they show calcium buildup, and our water is very hard here too, but you could contact the manufacturer.
Good luck on your decision!

We used Grand Effects for our fire/water bowls. All of this is extremely expensive, even at PB cost, but it's a feature we HAD to have. You'll love the visual. We've had the copper installed and in use for 5 months (water comes on each night as it gets close to freezing) and have seen no build up or discoloring yet (we expected some). Don't know the science behind it, but these materials are specifically built for pools.

We offer a range of options of scuppers and spouts that would look incredible with your design. Bowls are another beautiful option.

Any spout will patina over time, but you should certainly be able to treat it. Copper is an excellent material for pools and brass wears well also. Feel free to contact us if you have any specific questions, 949-329-8355