THE pet shop reckoned i fried the motor in my fluval U2 by letting the top vent touch out the water for a few seconds. as the flow was significantly reduced..so i had to buy another...THIS one did exactly the same in about 2 weeks (without runnin out of the water) took that one back and got a replacement. I think its a bad batch tbhi had mine running out of water for about an hour before - did no harm... but that was my TETRA IN300 which has decent cooling anyway.
Which filter was that then???

no the top output nozzle where the bubbles come out.top vent? do you mean the top of the intakes on the sides?
if they told you that would kill the motor then they are lying...
anyway, the motor is right at the bottom so it will always be moist...
In your opinion what is the easiest way (with a description) to kill a filter...
I'll start
SAND INGESTION!!!! (grinds away at impeller and completely renders impeller ineffective after a while)
Simple solution. Don't dunk your filter into the sand. I have a 75 gallon filter running 3 inches away from the sand bottom and it never picks any of it up. And a 20 gallon filter running about 4 inches away from a very fine sand substrate. Same deal.In your opinion what is the easiest way (with a description) to kill a filter...
I'll start
SAND INGESTION!!!! (grinds away at impeller and completely renders impeller ineffective after a while)
*sighs* Is this another thing I have to worry about with sand? Is there any way to avoid this?

Simple solution. Don't dunk your filter into the sand. I have a 75 gallon filter running 3 inches away from the sand bottom and it never picks any of it up. And a 20 gallon filter running about 4 inches away from a very fine sand substrate. Same deal.In your opinion what is the easiest way (with a description) to kill a filter...
I'll start
SAND INGESTION!!!! (grinds away at impeller and completely renders impeller ineffective after a while)
*sighs* Is this another thing I have to worry about with sand? Is there any way to avoid this?