160ppm nitrate suggestions?

[04V10]

I'd look at doing another huge water change for sure, ensuring that all the rocks and substrate get stirred up for the water change (you probably already know this).

Yes adding some fresh carbon would also be a great idea.

Next to that, if there is room to hang a basket or net, get some macro to put in there for a bit of help with the nutrient export (my friends have done this in the past when they had a nutrient spike). You could probably get some macro for free too from another reefer!!!