8000 gallon month leak in geothermal loop

Following up on a report that there is an 8000 gallon a month make up water requirement of the geothermal loop 

Will post the Delta record of flow in the geothermal water make up

 we are Troubleshooting to find out where that water is leaking 

there's also a report of the sound of water flowing in the pipes in the library when the very low-frequency drive  ramps down 

 this is a sealed system there should be no air in the system