I don't know that anyone ever goes to the effort of trying to catch them. Just grow them in your fuge and they will get pumped into your tank. You wont see them in your tank because of the predators, but they are there. When you stock pods, make sure you stock REEF pods. If you buy the little bottles that for example say "Tiger Pods", they will die. They are cold water pods and they cannot live/reproduce in tropical temps. They are designed to be used as food but not to stock your fuge. If you can't find REEF pods, then don't waste your money on the others, just buy some good LR and they'll hitch hike in. If your LFS is cool, they'll probably get your some rubble and some Chaeto from their fuge that should have plenty of pods in it. Pods reproduction cycle takes 30-45 days so it is likely to take 2 months before you really start seeing them all over.you can either scoop them up and move them yourself or they'll get pumped back in through the return pump, assuming there is one.