In sci.electronics.repair Danny D. wrote:

I bought a 1 HP Harbor Freight 69300 dirty water pump to drain
a green pool but it won't turn on at low water levels:
https://c2.staticflickr.com/6/5458/1...ee73cc98_c.jpg

The pump probably works fine.

I'd make suspects out of those two salamanders, probably unplugging
it before it's done running.

-bruce