That's what I do. I ran out, but just got some more.

I had a similar issue with my gfo reactor when I was running my dosing lines into the same chamber as the reactor. I guess this was the calcium and alkalinity reacting and binding in the reactor?
I moved the lines and haven't had this issue since.

I don't know if you can do this but if you can turn off a tank inlet valve rather than the pump the flow to the reactor will continue during the feed cycle. Just a thought.