water pump

Hey I'm just wondering, can you use a sponge filter with a water pump. I've already got a water pump spare big enough for the tank I'm gonna set up, I'm thinking about picking up just a simple sponge filter and pulling water through the sponge filter using the water pump. Will this work it's...

I'm building an auto water change system for my fish room (based on Rain Bird controllers and valves). I've gathered most of the parts I need except for water pumps. The DC pump recommended by my LFS looks great but it retails for more than $300 and I need a total of 4 pumps so I'm looking for...

so I just got a top fin 1.7 gallon tank from petsmart and the water pump has a switch for plus and minus I was wondering what that does because im not use to that kind