I've always had trouble keeping my frag plugs in the frag rack. My clownfish like to go under the rack and push them out. I've lost a number of nice sps frags from this. What is a good way to keep them secured in the rack? I've tried putting rubberbands on the bottom of the plug to secure them but that can be difficult with a full rack of frags. Is there anything else I can use to secure the plugs to the rack while they are acclimating to the tank?