I have an application where a slurry of salt (NaCl) in water needs to be pumped a short distance; approx. 30 ft. Flow rates are modest approx. 5000 Litres per hour. The head requirement is negligible i.e. not much of a height change other than the frictional head. What's the maximum concentration of solids we should shoot for? In typical slurry pumping applications what conc. do designers restrict themselves to? The proposed pump is centrifugal. Also, would it be feasable to gravity flow such a system? The available vertical height head isn't much. Approx. 10 feet. Would it flow freely under gravity or choke. Piping is currently 3 inch diameter steel. That's roughly a velocity of 0.3 m/sec which doesn't seem much.