Originally Posted by Okapi
Use a connector to add some length to that tubing. Hang the end of the tube that is outside of the tank lower than the end inside the tank and add an airline tubing ball valve to it. You can keep the siphon primed between drainings by closing the valve before the siphon breaks. When not in use, the length of tubing outside of the tank can be coiled up and taped to the back of the tank to keep it out of the way. Just make sure that you have the outside end lower than the inside end before you open the valve or the siphon will break.
This is very close to what I had planned to do although I had not considered the option of keeping it primed between drainings. Thanks for the idea!