filteration

[p watts]

hi there im new to tropical fish i have a 120 litre tank should i get the fluval u3 or u4 the tank is a fish pod 120

 

[fluttermoth]

Always go bigger; you can always reduce the flow if it's too strong, but the extra room for the bacteria is always good.

Don't forget that, if your tank's already cycled, you'll need to change filters gradually, or move all the old media into the new filter.