I had a sand storm when first setting up, which my Fluval 305 picked up a lot of, but most just settled back down. After the first day I cleaned out the canister and it was just full of the stuff.
If you still can, I'd suggest thoroughly rinsing the sand now. Agitate the heck out of it by hand, dump the cloudy water, repeat until the water doesn't get so cloudy anymore. Seems like a waste of salt mix, but now may be your only chance. Once you have fish, rock, etc., and the sand bed is established you won't be able to. You'll go through a lot more salt mix down the road anyway.
In my case, falling for the bagged 'live sand' from the LFS
and thinking that rinsing would remove the 'live' benefit, I didn't rinse. Now everything is set up and I can't. Wish I had. Also wish I had a better mix of granule sizes, all fine looks a little boring now.