Cave update: don't run mag drives externally (I know it says right on them to not run dry, but who listens anyway?). I tried to do a closed loop with one and it did not end well. After about 5 days of running fine, it managed to melt a hole into the sealed motor portion of the pump, shorting it and blowing a breaker in the house. I didn't immediately know it was the tank that popped the breaker, so when I reset it, it just popped again. Eventually figuring it out, I unplugged the pump and got the electricity back on. Got up the next morning to find the tank half drained onto the floor (basement workshop) as a result of the closed loop siphoning the water out and through the pinhole in the mag drive. Glad it was just a nano!
Tank is filled and rock is placed:
Dan