Hey all, I know how what a pain doing weekly res changes can be, particularly with larger set ups. I thought I would see about a battery powered liquid transfer pump, so I bought one on Amazon.com from Sierra Tools for $19.99. It takes 2 "D" batteries, and pumped my 4 gallon res in less than 2 mins.
I am lucky to be healthy, but I know many of you out there who have health issues that would make changing your res solutions difficult at best. I was very surprised at the power of the pump and the low price. If you are looking for something to ease the difficulty of growing medical marijuana in hydro, give this a try! jusbrowsin