I am not a pump expert but in an impeller type pump if flow is restricted too much or trying to lift past it's max head will it not cause cavitation and "not normal" water motion resulting in all kinds of water forces that could bend a shaft or break off a blade?

I have 4 little pumps... running a HOB fuge and reactors... all restricted but one. Never had a blade break.

Also not a "pump expert", so I guess anything is possible, but it would surprise me.

j&l replaced the pump, no questions asked.
i cant say im 100% sure nothing got into it, but its in a section of my sump with no snails, sand only thing in that section is my skimmer.
and my over flow box has a filter sponge on it, never see any solids in there.
i didnt think restricted flow could do it either, i thought it was more likely it burnt out the motor

sisters bringing the new one out tomorrow and ill give it a try again, hopfully there will be no issues but im never gonna have full confidence in it after the first POS crapped out.

Paddyop The hydors are powerheads only or is there another one I don't know exists? You can't run reactors with these.

Hydor makes little circulation pumps. They are tiny little things. They cost a bit more than the Maxi Jet pumps, but they're still easy on the wallet.