I wanna know if maxijets can somehow be used as external pumps in a closed loop system. My tank is fairly small, only a 20L...with probably about 25lbs live rock. With my rock set up, there isn't really much room for me to adjust the ph's how i want without hitting rocks or whatnot, and i'm not gonna take rocks out. Just these 2 maxijet 600's take up a good amount of space, especially when i'm trying to point the nozzles across the tank. Can they be somehow set up to run a small closed loop system on my tank so i can get the current and water flow that i want, while also freeing up space in the tank? Or will they be too weak and i just gotta get an external pump? If so, which one would you guys recommend i get...having to push the water up 2ft, maybe 3ft at the max.