pump to small?

[kien]

Originally Posted by the marine apprentice

if its a mag 12 you shouldnt have any issues running dry. just add more water to the sump so it stays higher. or just leave it turned down a bit with your valve.

+1 it sounds like you just need to put more water in the return section of the sump. If you fill up your return section first, to the height of your baffle (assuming you have a baffle), then plunk the mag12 in and turn it on it will suck up water out of your return section fast and needs water to fill the return line. That's probably why the water is running low. Once the return pump is running, fill your return section to the level that you want to run it at. Depending on how large your return section is, this is the section that will show loss in water due to evaporation. So if it is a small section it will drop fast due to evaporation and you will need to top it up. The water level in the return section will also change with any change in your overflow box due to the herbie overflow. More water in the overflow chamber = less water in the return chamber of sump.