Basement Watchdog. Available at Home Depot.

Pricey YES, the best YES.
(They use Salt Water Bilge pumps, and smart charging).
I've used mine as the primary setup when the real primary failed. Note WHEN not IF the sump pump fails.

Neighbor had the TOP O LINE backup setup installed by some local plumber, I've had to help him fix it twice (in 2 years).
My Watchdog is 15 years old, I did replace the pump recently, this is the 3rd Battery, and I had the system "rebuilt" years ago. They are local for me.
And my "Sump" runs constantly. In the driest weather several times an hours, in this rain, every 10 minutes

DON'T GET THE ACE IN THE HOLE

__________________
KLK, MCSE

1990 500SL

I was always taught to respect my elders.
I don't have to respect too many people anymore.