Rubber couplers worked great, 100% seal, and allowed me flexibility glued pvc would not. Easy to disassemble and reconfigure for other ponds with different depths and geometric configurations. Entire system fits easily in truck bed.
2" ball valve on back end, top [through which you fill siphon] and pond end. Below the ball valve on the pond side I go down another 5' or so with a T and 2 5' sticks capped with 1/2" holes drilled. This prevents any fish/turtles from being stuck in the siphon which has happened to me several times draining ponds.
Design was simple enough for me to construct, deploy, take apart and store solo. Couplers are cheap and most of the PVC I had on the farm already. Rex helped a lot with this configuration - thanks Rex!