Wet/dry filters..
 

I am wondering whether this type of filtration offers an advantage over a
standard canister set-up. (I use an Ehiem 2028.) Can anyone tell me of
their experiences with this type of filtration? Have you used in with CO2
injection? It seems that a wet/dry would tend to liberate too much CO2 to
be desirable for planted tanks-- but I note that some people use them. What
is the advantage? -Bruce Geist