As an aside, my Peppemint shrimp seem to be sexually attracted to my MP40s. I had been using the foam covers until a decided they caused too much reduction in flow, so I took them off - and within a week I lost three shrimp
Lesson being either spend $50/week on (I asssume on (lol) non-edible shrimp) or cover your propeller designed pumps with the included foam covers, unless you want to lose little guys.
Was really sad too - one morning I turned my main lighting program on/ my morning water perimeters on, which was the clue for my six or so shrimp (3 peppermint, 1 cleaner, 2 blood) to wake up, and an hour later, two of the three newest (three peppermint shrimp) had already made a disheartening "thunk, chip, whirrrr! and had been through my Ecotechs. Reason didn't come to me yet, so I left things alone and the next week, almost exactly after lights/pumps on a third true peppermint shrimp "made the voyage". I was rather sad because this was a living creature that my Ecotechs, especially this time, decided to peel like he was a shrimp at a buffet for humans
In the end, I have my two blood shrimp, no peppermints. IMO covering my MO40's with the foam guard really does reduce flow, so I"m at an impasse - most poeple with MP40s/Vortech return pump keep shrimp, and while I've got the two blood shrimp going fine, I'd love to hear about what others are keeping without reducing your MP40 via the foam cover. I have a 180 gallon tank plus sump for reference.