It was the siphon action, thank God! I did an experiment. I noticed that a little suspended dirt had settled at the bottom of the bog snorkel, so I pumped some out, then unplugged the pump, leaving it in. 5 minutes later, it was still flowing out strong! I am certain that is what happened with the main pond. It was a good lesson to learn now, though, before I get fish. That would have been sad!
I adjusted the rocks in the intake bay and now it is pulling stuff in! I tested by putting a mosquito dunk at the far end. It doesn't take long to end up in the bay!
I have my De-chlor and More in the water. On Thursday or Friday, I have 50 rosy red minnows coming!
I really have no idea about the amount of water. I am guessing 1500 to 2000 gallons? I need to get out with a tape measure and do some math.
I do know that the shallow end is calf deep. The next level is knee deep. The next is mid-thigh deep and the deepest part is not quite hip deep, but close.
I will attach a few snaps of the waterfall running - and the bog!