Hey guys, I'll admit I'm a real noob at this. I got a siphon from petco that you basically shake underwater and it's supposed to start siphoning water out. My problem is (I have a 20 gallon) that it works well for the first few gallons but when my water level gets lower it refuses to prime properly. Consequently I end up having to use a pitcher to get more out if I want to do more than a 25% water change. Anyone else have issue's with their siphon? Next problem is putting water back in. I use the same bucket I took water out with and when I'm pouring water back in no matter how gentle I try to be it ends up displacing the gravel at the bottom. Considering I'll have to be doing lots of water changes the difficulty of them has me slightly discouraged. help!