Just like the Steel Eagle, you adjust the height with the bolts of the castor wheels.
It is a fine adjustment to get it working on the surface.
Sometimes you need more vacuum, sometimes you need the surface cleaner a little bit lower. I know it can be frustrating sometimes getting the adjustment right but once it is there, things are great.
I know it will be a pain but little adjustments by little adjustments so that you can see what is happening as you adjust it down or up.
One of the guys mentioned if you use the 15 degree nozzles, it will not throw out as much water but.......for the really filthy concrete it will clean better as long as the concrete can handle the pressure, if it is a parking garage, it should but I would still do a test spot just in case.