Greg Esres wrote:

My tiling book says to sand the concrete with a coarse grit sandpaper
and then wash with muriatic acid. A friend of mine thinks muriatic
acid is way overkill and just washing the floor would suffice. I'd
rather avoid using the stuff. Any thoughts?

(BTW, concrete is interior slab...seems smooth. Troweled surface?)

Nuts! We didn't even wash ours. Just tore up the carpet, vacuumed, and
the contractor did the rest. No suggestion made as to cleaning it. Is
it bare concrete? In living area?