You're better off getting/using a semi-trash pump. It can handle an occasional solid (small rock, twig, etc.) and it won't damage the pump. They are more expensive, but will last longer. Look at Northern Tool for them too. Get one with a Honda motor - much more bullet proof than the others. Search here for "trash pump" and see what comes up.

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3/4 to 1 1/4 ac pond LMB, SMB, PS, BG, RES, CC, YP, Bardello BG, (RBT & Blue Tilapia - seasonal).