Korallin Calcium Reactor

Hey everyone, I have a 150 gal reef and just recently acquired a new Korallin Calcium Reactor. After reading the manual and following the directions, I have the reactor set up and it was running great. I have the water feed coming from a line that is an acclimation hose hooked onto the side of the tank. The reactor is underneath the tank level with the refugium. I also have a Milwaukee pH probe that is attached to a solenoid to shut the reactor off when the pH falls below 7.8. The issue I'm having is that when the solenoid does shut the reactor off, the pump for the reactor loses its prime. So I have to undo the line from the tank going to the reactor pump and bleed it then reattach to gain prime. Wondering if there is another way around this? Do I need a larger water line into the pump? Possibly need to elevate the reactor? Any suggestions/help would be greatly appreciated.