We just opened our pool and there was a lot of dirt in there. I vacuumed to waste the bulk of it, but there was still some left over from when we couldn't really see the bottom. I just hooked the vacuum back up but didn't switch it to waste since it wasn't much, but it seems to come back out of the returns? Does this mean our sand probably needs to be changed? The pool is about 15 years old; we've only been here for 2 years though and have no idea if it has been changed previously.