Warning about Seachem Matrix and Return Pumps

[djam]

First, let me say I love this stuff, I've been using it for 2 years and only have 200lbs of rocks instead of 300 or 400 that I should have. I went to add more more to my tank yesterday, I put the matrix in an extra overflow area in my sump. Each bucket full is about 100lbs worth of rock (it weights like 2-3lbs). Some of it floats it is so porous, I scooped the extra floaters out and threw them away. Well it appears, I didn't get all the pieces and one of them got sucked into the return pump, yeah I was missing the cover for some reason. I planned on having to replace the pump one of these days so I had a spare and it took 20 minutes to swap it out. The first time I used it I put it in mesh bags... I wish I wouldn't have been so lazy this time....