Just about ready to throw in the towel grrr

[Aquattro]

Greg, this is just one of those downs that make the ups that much more rewarding. Throwing towels won't fix it, and if you pack it in, you'll regret it in three weeks. Figure out where and when things changed, and work backwards. Maybe pull out the zeo for now, do a 50% water change, siphon and sand bed with one of those vac things, keep the skimmer cleaned daily, and use filter socks if you aren't already.
Slow off feeding, rinse any frozen foods, rearrange flow every few days to remove dead spots, and in a month you'll be happy again. Or too tired to care. Either way, get at 'er!!