A plastic hose works, as mentioned. You can buy a clip to hold it to the tank so that the hose doesn't fall and make a mess. You will have to suck start it. Be sure to get hose that you can see through. You don't want that water in your mouth. You can also buy a gravel vacuum at your LFS. It is the same thing but the vacuum has a wider end. You can shake it up and down to get the siphon going.