at the bottom side, of the pipe were water is coming out. create a "U shape" in the piping. this will help keep air from finding its way back up through the pipe.
the "tee" at the "highest point" in the plumbing. i would caution use of a "pipe test plug" or less you have the more expensive ballon shaped ones. the cheapo's can let air get sucked in. and by the time you crank down on the wing nut or handle of the cheap test plugs, you break something.
a screw on plug can work nice, preferable a "clean out" plug that has a good size square nut on the end. that you can easily place a pipe wrench or pair of channel locks on. to help tighten / loosen.
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as far as priming the siphon. i bought the "Cheapest" sump pump i could find. not because of the money, but rather, how much power it required. and then obtained a 12V to 110V converter that plugs into the cigerette lighter, that then allows you to run a small appliance like a light or fan. (pick up at most electronic stores), a heavy duty extension cord. and a garden hose.
if you buy too big of a sump pump. you will cause the converters to trip, and you will be constantly fighting the converter, and/or cause damage to converter.
if you have a small size vehicle truck or car. you might want someone in the vehicle keeping the engine partially rev'ed up, when using sump pump, found out hard way, and ran battery dead. and had to walk a mile to get another vehicle up by the house on farm. just to get a jump.
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you will most likely want to put some sort of "grating" or cage around inlet on the siphon. i have had good size catfish, bass, blue gill, frogs, sticks. get caught to edge of a milk crate, that i was using as a grating for the inlet. also lost plenty of minows and tadpoles as well.
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be prepared to re start siphon up once or twice a day. "air" can come out of the water. and can find its way in the highest spot in the siphon. and stop the water movement.
