Hey if you guys are having trouble keeping your plants down I've got a decent solution. Grab some quickcrete from Home Depot, mix some up in a small Tupperware container, enough to cover that crappy plastic base, and set the base in the mix. In 24 hours wiggle the Tupperware off the new concrete base. Rinse it off and chuck it in. It will always sink. You may want to rubber band the branches/leaves of the plant if it's bigger to keep them out of the cement mix while it's curing. Cichlids are jerks about moving stuff, but it's a lot harder for them to move objects with considerable weight. Hope that helps.