Thanks for the advice guys. However, my setup is a little inconvenient. I have the tank back-to-back with a window that is all blocked off with thick styrofoam and a window fan. There is just enough space underneath the window fan to slip a 5/8" tube leading to the outside garden. So, I'm looking for something I could switch on and off. I have a hand pump, but it's still a cumbersome procedure.
I'm trying to find out the most durable and efficient AC or DC powered pump for water changes or just vacuuming debris.