Additive to an aluminum sulfate and water solution to lower pumping pressures
The needed pressure depends on liquid viscosity. The significant decrease of water solution viscosity cannot be achieved by adding of minor additives.

It could be achieved by methods that may not be applicable:


Decreasing concentration of the solute
Decreasing viscosity of solvent by different solvent composition
Increasing temperature of solution. A rule of thumb says viscosity decreases by 3% by increasing temperature by $1 ^{\circ}\mathrm{C}$.