Nitrates:
https://www.reef2reef.com/threads/nitrate-too-high.412614/
Copper:
https://www.reef2reef.com/threads/copper-side-effects.429017/
Ich:
https://www.reef2reef.com/threads/how-to-cure-ich.422009/
I've said it before, and I'll say it again. You need to slow down.
My advice:
If there's anything still alive in the tank, do it a favor and give it back to the store where you purchased it.
Let the tank sit with no livestock for 4 months. It's a 170g tank, so change about 20g of water once a month. Run the lights as normal, as if the tank had corals and fish in it. Don't add any fish or animals. Don't add any corals. Just see if you can get it balanced and stable first.
After 4 months, test your water parameters and start a new thread to discuss.
I know some people are going to say that's crazy or stupid. Let's see if we can get a tank full of water stabilized and get some coraline algae growing first. No sense killing more innocent animals and tossing money down the drain. Back to basics -- stabile tank parameters first--- for as long as it takes to get stable. Then ONE step forward. Not 8 steps in a month. ONE.
This is so sad for me to read. It's not necessary to go about all this senseless killing of animals. You can't kill enough and eventually the strong ones will show up and survive. You have to get a stable tank first and then go very slowly. This poster started the first post about finishing the cycle in June 2018. Here we are 3 months later -- not 4 -- THREE months later and we have numerous dead animals - random dosing of chemicals with no idea why or what they do or how they react.
Want to start another thread and see if you get any better answers from that one? (SMH)