Wow, thanks for the heads up! I'll look into removing the Nature 2 mineral cartridge (I've seen other posts on here about how to do it without damaging the cap), or just cutting it out of the line entirely (it's just patching a PVC pipe after all).
It's amazing the amount of trouble I was looking to get into if I followed the pool builder's advice and used all of their recommended chemicals. They've partnered with BioGuard which pushes all kinds of "Blue" products, a buzzword which I read elsewhere on here is a key hint that copper is included. I checked the BioGuard Silkguard tablets and sure enough they include just under 1% copper sulfate pentahydrate (not to mention the CYA). They would have had me regularly using trichlor tablets with copper, weekly shock treatments with multiple bags of dichlor, 3 oz/wk of 13% copper-sulfate algaecide, and 11 oz/wk of their phosphate-removing clarifier potion.
I'm more thankful than ever that I found you guys early on.
Rather than being constantly disheartened by an out-of-control pool, my biggest problem now is what to do with hundreds of dollars of worse-than-worthless chemicals that are sitting in the storage shed...