Make sure your soap system is working correctly. You could have a bad foot valve, the Hydrominder could have a clogged inlet or foot valve screen, the valve may not be opening fully and it's not drawing soap. Check these things, and if it all looks okay dump some soap straight into the tank. If none of that helps, look for a screen in the tank or a check valve between it and the solenoids, or disconnect a line to a solenoid and drop it to the floor to see if you get gravity flow (That might be a first thing to try).