- Crystalloids

Ringer’s Lactate:

[Isotonic] pH = 6.5, 274 mOsm/L.  Contains Na, Cl, K, Ca, and lactate.  The idea here is that the concentration of electrolytes is supposed to be same (more or less) as that in interstitial fluid.  This is the stuff that surgeons like the best, they'll keep it running for days (which is okay).