Ink Leveller Add-On That Makes it Work Right

I recently discovered a small tip for ink level control.  Please take a look at the ink level bar above.  It controls the level of ink in our yellow ink fountain.  The bar across the fountain supplies the ink, but please notice the the tips just underneath it.  Each tip has a small valve.  We put them on recently for two reasons:

1. The leveller did not supply ink evenly to the entire fountain.  It's a natural that it loses pressure as it passes each valve on the way to the end of the fountain.  Notice that the tip closest to you in the picture is wide open.  As you go to the other end, the valve is almost closed.  Why?  To account for the drop in pressure.  Now our fountain fills evenly when it turns on.  The result is ink that is fresh all the way across the fountain.
2. The leveller does not leak when not used.  Sometimes we pull it out to change ink or clean the fountain.  We now simply turn off all the tips and nothing leaks out.