This is due to a bad seal between the tower and the metal threads on the AquaCure. This would either be caused by incorrectly taping the metal threads or forgetting to place the black o-ring between the tower connector and the tower.
To create a good seal, 15 layers/wraps of Teflon tape must be wrapped around the top of the metal threads before screwing anything onto them. Any time those threads are exposed by removing the old tower model tower or the new tower connector, the tape will need to be reapplied.