Inspired by mikebaier's Neptune Apex PMUP Mount (hence the remix credit).
This mount keeps your Neptune Systems PMUP upright in your top off container while enabling you to use an optical sensor to safeguard your pump from running dry (Apex programming and necessary hardware required). I've included mounts for both horizontal and vertical sensor orientation.
NOTE: STL files pulled do to people selling the design and not honoring the license. The attached STL is also my design, but not related to this "thing". Please PM if you are a hobbyist that would like the original SLT's.