I bought a new leo gecko and his poop has sand in it?

The place I got him from is supposed to be a reputable reptile shop, though I am doubting their actual credibility now... First of all one of the people couldnt begin to guess at this geckos sex so he got someone else who said the gecko was female, I was quick to point out he was wrong since was CLEARLY male no doubt about that, and he them proceeded to tell me it wasnt possible to tell until the gecko was 2 years old O_O...noo..nooooo. I also noticed the leos were kept on sand but I was quickly reasured that they weren't fed on there, nor kept on it all the time (apparently they moved them when the shop closed)

Well that was two days ago, and things seem fine...no shocking or worrying behavior from the gecko, he's pretty timid at the moment but I guess thats to be expected... But I was checking his poop ( I know that sounds weird... But it pays to check! you can tell a lot from an animals poop) and there was sand in his poop!

He isnt impacted luckily since he IS pooping, but what should I do to help get the rest of the poop out of his system quickly??