99.5% acetic acid with calcium

[eli@fijireefrock.com]

i am not much of a chemist
a couple of days ago i bought acetic acid 99.5%, calcium carbonate 98.5% USP grade and kalkwasser and my oolitic sand from my reef tank.

in 3 different cups i added a 1tsp of each of the calcium product above
and 1tsp of the acidic acid into each cop

few hrs later

calcium carbonate no changes
kalkwasser all desolved with enough acid to dessolve more
reef sand desolved with enough acid to dessolve more

why did the calcium carbonate not dessolve