Just wanted to inform people who had been following this thread, that after a month or so of running the pumps on the tank, the overflow now has a small leak....so I will be putting in a pvc standing drain pipe into the bulkhead as an extra precaution. the leak is very slow and no problem when the pumps are running, however, I have no idea if this leak means that the silicone is loosing its hold or what, or if the leak will over time become worse and faster?...so I will leave the overflow in, but add the standing pipe to avoid having a flood sometime while I'm on vacation somewhere.....There is no rockwork leaning on the overflow, and has been no "trauma" to the overflow...it appears its just as time moves on, losing its "grip".... :thinking: