I'm thinking about putting pulsing xenia on a rock in my sump that I have above my tank as I like the look of pulsing xenia but don't want it in my display tank as I have heard horror stories about pulsing xenia completely taking over tanks and was just wondering if the pulsing xenia would manage to spread from the sump to the main tank through the water. The water is pumped into the sump and gravity fed back into the main tank from an overflow if that makes a difference.