Thanks for demonstrating that you don't have really high chlorine.

Here's what I think is going on in your pool:
Use of trichlor for primary sanitization has built a very high CYA level (you already know this).
You have kept chlorine level low compared to CYA as recommend by the "mineral system" vendor.
The metal ions (copper and silver, I bet) have helped keep the water clear as the active chlorine level (ratio of chlorine to CYA - not measured chlorine level) fell.
The chlorine / CYA ratio has gotten to the point where there's not enough active chlorine to keep the pool clean despite the presence of metal ions.
Algae (not yet visible) is starting to grow creating the chlorine demand you are experiencing.
The powdered chlorine products you've applied haven't reached a chlorine level effective to kill off the nascent algae.

The simple recommendation is to shock the pool to 30ppm FC but there's a catch. The metal that I believe is in solution in your pool may stain the pool when chlorine is raised. You can test this with a clean, white, 5 gallon bucket. Fill it with about 4 gallons of pool water and add a tablespoon of bleach. Give it a stir and wait a day or so to see if it stains. If it does stain and you want to avoid stains in the pool, post the bucket result here and we'll work out a plan.

If there's no stain or you don't care about staining the pool, you'll need about 10 jubs of 8.25% bleach to get to the 30ppm FC shock level and then you'll need to keep it there until you lose less than 1 ppm FC overnight, you have 0 or nearly 0 CC and the pool is clear. Run the pump 24x7 while shocking. Leave the pool cover open if you can - some of the byproducts produced while shoking the pool may damage the cover.

Phosphate remover is expected to cloud the pool - clean the filter. I'm a little concerned about a hardness reading of 750. Are you sure this test was done correctly?