Water pump sucking air ?, best way to drop the underbelly ?

I'm not your underbelly guy, but I've read here, where the pump pickup (suction side) and the tank drain, were T'd into a drain bung at the low point of the tank.

But the drain valve, the one used to empty the tank for winter, etc. or the hose connections to it, had pinhole leaks. Water might not drip out, but the PUMP could suck Air In. That in turn compromised the operation of the pump.