Just to put the pic into context, that's a 125ml bottle (4.2 ounces), it's only 1.5 inches in diameter and 4-5 inches tall. the q-tip sounds like a plan, i like the siphon idea, but it overcomplicates a simple problem. I believe a screen is used on the suction tube to keep whatever you are sucking up from coming out of the container, like a vacuum and its filter. If ever you go that way, I'd use cotton, cause you don't want to be inhaling any sand that might make it through a metal screen(what would you use? a baby food jar?).
Is it true if you drop a drop of water on the center of the gemmae cluster, they go flying? I can't wait to see that happen.