concrete shower floor painting/recoating

I'm looking for some advice on a concerete shower floor. It's currently painted white with some sort of enamel or epoxy but that is starting to flake pretty seriously. The concrete appears to have some granite chips mixed in to it. I think I can mechanically get all of the old coating off with a scraper because there is very little adhesion between the white coating and the concrete itself.
Here's what I've learned from some googling: There are some "epoxy" paints out there, I've heard of 2-part "real" epoxy's, I've seen some mention of pool paint in my digging. Some recommend muratic+water rinse before applying coating
I had a tub/shower guy out here that quoted $400 to try something he couldn't guarantee because the floor is a tricky material or some such, and the coatings weren't meant for it. He mentioned that there was a lot of pitting on the surface of the concrete as though someone had used a very harsh acid (perhaps muratic?) on it before that didn't seem to do the concrete any good.
Anyone had success on such a surface aside from chiseling it out? Cost is sensitive and it doesn't have to last forever...
Thanks for any insight! Jim
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file
Upload is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.