Comparison Between Pumping and Vacuum System

I am a sub contractor for CalFire and am building another water tender.   My last truck had a 750GPM pump for drafting and pushing water.In my work I transport water to:  Fill Engines, Water Tanks, Pumping into Private tanks,  Pull from hydrants.   I was wondering if the Vacuum system would over pressure the common systems?I also mix Thermo-Gel in our current tank system.   Can you utilize the Vac Tank as a mixing vessel and then pump it out of a hose at 125 PSI or through a turret?What pressure can you produce to spray water for wetting roads in a Pump and Roll Situation.  Dust control and rehab? Can you adjust the PSI when spraying?   We spray wash solar panel arrays and wonder if the spray psi is adjustable? My current project is a 1992 Pierce Arrow 4WD from Antartica with 6000 miles on the odometer.  I am searching for an appropriate tank system for the truck2000 -2600 Gallon depending on weight and pump set up.   Any assistance is appreciated.Jack KimmichHollister California