The Poly filter pads work great. I had the same issue with a copper bolt a few months back. I used a total of 3 of them. After the 3rd one (Left each in for a week) It stopped changing blue. I also suggest getting Prime and dosing that about twice a week as it 'detoxify' copper (note that while designed for metal levels found tap water, I felt more secure in whatever decrease in toxicity it provided). Should help prevent any more deaths until you get it all removed.
I also did a 25% water change twice a week for about 3 weeks. I've left the last poly filter pad in there for about a month now (i guess it's time to toss it but it hasn't changed color at all). Definitely stir up your sand and blow off the rocks during each water change to help remove and trapper/settled bound forms.
So it will be a few weeks before you totally clear all copper without shocking the system with HUGE water changes. I'd also invest in a copper test kit too. About $6 or so.
Good luck and sorry about the loss. But you can recover with a little time and currently my tank is back in the swing of things and supporting corals/inverts again. I even lucked out too. When I saw my corals dying off, I placed the rock remains in my nano tank and while most were lost, after a few months I noticed where it looks like my xenia melted away, a small piece managed to survive and is now growing back.
At least you know your fish are ich free!