I just use my mouth... people call it gross, but the water is no more dangerous for you than it is for your fish. And besides, if you do it right, you shouldn't get water in your mouth anyways.
Put the gravel vac in deep enough so it's filled with water. Hang the hose over the edge and down so its below the tank. Suck on the end of the hose SLOWLY until the water goes over the edge of the tank and starts flowing through the hose. Quickly place the hose in a bucket or whatever you use. Works every time.
Put the gravel vac in deep enough so it's filled with water. Hang the hose over the edge and down so its below the tank. Suck on the end of the hose SLOWLY until the water goes over the edge of the tank and starts flowing through the hose. Quickly place the hose in a bucket or whatever you use. Works every time.