ghengis

I have always wondered, with sumps, if somehow diffusing the CO2 into the return chamber, rather than the tank, might not be a little more effective...? So the diffused gas gets to spend a more time in the water column, before being (potentially) gassed off at the sump inlet chamber... Would that be worth a try??

geeks_15

In my setup, from the sump the pump pushes water through an inline CO2 diffuser and into the tank. Its working well so far.

adechazal

Backing up Jeremy, I also run a sump on an Oceanic 180g with dual overflows and compressed CO2. There are pros and cons to whichever setup you use, I chose a tank with a sump in case I wanted to convert to salt water one day. I now know that sumps are a great place to hide all the equipment but the biggest benefit in my mind is that evaporation only affects the sump level, not the tank.
Aaron