Well if it's called a Gravel Hoover, then I'd guess it's for hoovering the gravel! Use this indispensible device once a week to suck the fish crap out of the gravel. Then, replace the water you took out with fresh water. You're saying "ok thanks dude for the info so far, but how do we hoover the gravel with this strange looking device?" Well, I can help you with that so listen on. You need a bucket, so go get one. OK, welcome back. Now, submerge the vacuum end of the device in the water and let it fill with water so there's no air in it. Then put one of your many fingers on the end of the other end so as to close it off. Then lift the vacuum out of the water and hold the device so it forms a U. Now let your finger off the drain tube (carefully!) so the air can escape. Is the water level close to the end of the drain tube? OK, we're ready to rock. Put the vacuum end back in the tank, and direct the drain tube into that bucket you got earlier, and remove your finger from the tube. Cool, huh? The water is draining into the bucket! Well, now comes the fun part. Stick the vacuum into the gravel and watch the fish crap get sucked up. Once you got it all, or some of it at least, you're done with the hoovering part and you should procede to the refilling part. Use dechlorinated water that is close to the temperature of the water in the tank.
