I would pass on the Mini-jet, I just don't think it would be the best choice for you. The 900 utility pump would work well, as would the MJ900 or MJ1200. The nice thing about the 900 utility is that it comes with a flow control valve on it, which is nice to have "just in case."
If you're dosing kalk through this, then look at the Aqualifter like Scott recommended, or a peristaltic pump.