A wet-n-dry shop vac will empty the filter. If you don't own one, probably one of your handy friends or neighbors does.
I guess I'll get to be the bearer of bad news and tell you what you already know deep down. You need to empty that filter out again and recheck your work. Something didn't get seated properly or you overfilled it. There's a mechanic's rule of thumb that says, "The last thing you worked on is the first thing that breaks." It wasn't blowing sand before you messed with it, and it is now, so it's something you did. Hopefully it's just overfilled. That's the easiest thing to fix.Help please. When I put my hand in front of the return it gets covered in sand. Same with backwash. There is no doubt whatsoever it is sand and lots of it. Where do I begin?