Sump pumps in a box, like the Rule
, are a problem waiting to happen.
To make it worse, they are in a sealed box, at the lowest point, so when it stops working, usually as a result of blockage from hair and soap scum, the first thing you have to do is open the sealed box which is full of crap and water
. Thats all going to spill out making even more mess.
A diaphram pump is like a heart, it needs the one way ,non return, tri cuspid valve to prevent the previous surge from returning, allowing the next stroke to fill the ventrical.