Little Giant Bronze body sump pump with a diaphram switch. lasts 20 years easily and even then its the switch that goes and it can be rebuilt. Best sump pump available anywhere.
Little Giant Auto. Bronze Sump Pump 54 GPM 4/10 HP # 8-CBA, 508357
Same company also makes a plastic coated cast iron one foir less money but I don't know how long it will last. In 48 years at my house I have had only 2 of the bronze ones and the second one is like new.
I also would try to set it up without a check valve as often they get stuck closed then you have a mess.
Biggest problem is if you have a power failure though.
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