51^mhos cm² equivalent 75^mhos cm² equivalent (51 ₇₅₎mhos cm² equivalent ×  1.7  ×  10^5equivalent liter ×  10^3liter cm ×  10^6µmho mho 2.2^µmho cm WATER PURITY DOE-HDBK-1015/2-93 Principles of Water Treatment CH-04 Rev. 0 Page 30 The equivalent conductance of Na   is , while the equivalent conductance of + Cl  is .  The conductivity of the solution is - , which is well above the limit.  Even extremely low concentrations of ionic impurities can easily be detected.  The most probable cause is a depleted or damaged resin bed that is no longer capable of removing ionic contaminants.  The depleted bed should be removed from service, and a fresh resin bed placed in service. For  most  applications  in  nuclear  facilities,  the  specification  that  is  identified  as  Very  Pure (1.0    mho/cm maximum conductivity) is used.  Ultra Pure demineralized water is normally only required in laboratory situations and is mentioned for information purposes only. Summary The important information in this chapter is summarized below. Water Purity Summary Water Purity is clarified below. Approximate Degree of Purity Maximum Conductivity(µmhos/cm) Concentration of Electrolyte, mg/1   Pure 10 2 - 5   Very Pure 1 0.2 - 0.5   Ultrapure 0.1 0.01 - 0.02   Theoretically Pure 0.054 0.00