You were on the right track with the garbage idea.
Any overflow box that needs a pump to keep it running isn't designed properly.
Don't know why CPR keeps selling these pieces of crap. We used to carry them, but, I refused to sell them to customers. I think CPR is the reason overflow boxes have gotten a bad reputation.
I've used properly designed U Tube overflows for over 10 years and never had one stop. JMO