Originally Posted by HoneyDoII
Do you have outlet valves on each of your water tanks individually? It sounds like they are all closed. When you initially turned the water on it sounds like it pumped the feeder line dry and no fresh water is now gravity flowing to reach it.
That is a very good suggestion!!
On our boat, each tank has a ball valve at its outlet. If these valves are closed, the system would produce the sort of symptoms described.
However, the OP indicated that the system was working prior to his filling the tanks, so ????? Did he or someone else possibly close those valves when the tanks were filled?