Doesn't like Kool-Aid
Join Date: Feb 2003
Location: Hawthorne, New Jersey
I would add the second filter, if it is something you can afford to do.
The second filter would act as a mechanical filter and increase circulation in your aquarium, while the first XP3 continues as your biological filter and the power plant for your CO2 reactor. A powerhead will move water for you but the second XP3 will not only be moving water, but filtering it also. The second XP3 performs two functions.
I do the same thing with two Eheims, and I am very satisfied.