Ballast not filling

[wishbone1961 1]

Still having trouble with my ballast filling (starboard side). Strange issue. Its intermittent as well...which is driving me nuts. 2007 Enzo SV216. Has the four sprinkler valves. Clean filter. Pump is running. Impeller looks mint. I pulled the filter and turned the pump on and water came out. The strange thing is that the last two times it did this, once i removed the hose from the output side of the pump, it started working again. At least until I got it full. The very next time though it did the same thing. 

Is it possible that there is air pressure keeping the pump from priming after I had stopped filling? 

My service tech told me before I should get rid of the sprinkler system too. Thoughts?

[Dillyrev 0]

Mine will fill but wont empty, pump is running and sounds fine. 

[DrPringle 10]

Toss the sprinkler system and your problems will go away

[Wylie_Tunes 146]

Yes! I would not spend 1 $$$ or minute trying to fix a system with sprinkler valves. Slow and problematic.