text: Air or other gas dissolved in the fluid it can come out of solution as small bubbles (entrained air). If these small bubbles have sufficient buoyancy, they can rise to the surface and together form foam. Mechanical factors that may generate entrapped air:
  * Leaky seals on pumps
  * High pressure pumps
  * Poor system design (tank, pump inlet, outlet and manifold design)
  * Pressure release