DarthTedious is being polite. The majority of the reservoir volume is unavailable to gravity feed the MCs. As soon as the fluid level drops below the level of the MC hoses, no feed will occur. You may not need a lot more, but if you want most of the volume available, the bottom of the tank needs to be raised. You have very little available to gravity feed.
You can prove this with a plastic container, a short length of 1/4" clear plastic hose, and a 1/4" straight barb fitting used for drip sprinklers. With the hose barb in the bottom of the container and the hose pushed onto the barb, hold the end of the hose even with the top of the container and begin filling it with water. No water will come out unless the end of the hose is dropped lower than the top of the container. Then it will quit running out when the end of the hose is the same as the level in the container.
I'm also an engineer. I hope Tony isn't. This might be a grade school science demonstration.
http://www.wikihow.com/Use-a-Water-Level