powerhead suggestion

We use a P 1140 on the 80, but as posted the 660 would be adequate for your 40..........:)
 
What kind of fish do you have? Are you looking for the cheapest possible solution? If you have some fish that would like a bit of flow, and dont mind spending a bit more, you might want to check out the Koralia pumps. They are awsome for moving a lot more water with less power consumption. Plus they create a wide dispersed flow rather than a jet. For example: http://www.drsfostersmith.com/product/prod_display.cfm?pcatid=15955
 
AquariaCentral.com