k wrote:
I have a shower and the grout on the floor has hair line cracks in
it. The shower wall is fine, no problems. Upon looking closely at
the grout I found that there are holes through out it. The holes
don't seem too deep, the don't seem to be all the way through it more
like bubbles in the grout at the time of the application.

Can I simply just cut out the grout from the hair line cracks or
should I try to cut all of the grout from the shower base?
Can I spread grout across all of the tiles even ones that I didn't cut
the grout from? Will it bond?

Any advice would be greatly appreciated.

I can't help but picture a shower with poor support and a "spongy"
floor. It will just crack again and again. Hopefully I'm wrong.