Maxi Doser questions for Auto Water changes

I'm in the process of setting up my Auto Water change station. I have to move water about 15 meters from my mixing station to my tank. Then I have to move the water from my tank to a nearby drain (15 meters).
I'm looking at setting up the Maxi near the tank.

1. Can the Maxi pull water from 15 meters to my tank? How best to control air in the line?

In a perfect world I suppose I would have two Maxi pumps. One in each location pushing water. But that's not very cost effective. Perhaps GHL can come out with a Single head Maxi?

15 meter (50ft) is at the max recommended limits. As long as it can be a straight horizontal shot 50 feet across, it should work.

Unfortunately it would not be straight and level. The storage tank for the fresh saltwater would be in my garage. The water has to go from that up to the ceiling/attic(2.5-3M up), across the attic then down to the tank and sump.
Going up the first 3 meters would be the hardest part for it.

Did you set up a auto water change? If you did could you tell me if this is possible with just the maxi or do I need to get 2 float switches?

It can be done with TIMER functions and no GHL float switches, but this will forego the built-in fail safe (max-on time) which forces the pump to stop in case of running over the allowed time limit.