Based purely on my own anecdotal evidence, the inline atomiser used less gas, and produced better results for me, and my set up.
I've no scientific evidence to back this up: just my eyes....
You can put inline diffuser in filter inlet piping, allowing the passage through the filter to dissolve the micro bubbles. But this can have issues, filter "burping" due to collected gas, filter seals can/will be affected by CO2 either softening or hardening, but main one is the inline diffuser will need cleaning every couple of months as it has dirty water passing over it. I have had my diffuser on my filter outlet pipe since 2012 and not needed to clean it.
Sorry,may have misunderstood OPThe co2 in the filter inlet or an inline atomiser on the outflow of the filter,
Thanks
Output
Sorry,may have misunderstood OP
I was comparing a ceramic diffuser under in the filter inlet;against an atomiser on the output.
I'd stay clear of putting it on inlet based on my experience. Burping and quite noisey. I've more or less tried everything other than a homemade reactor. I'm considering getting a small in tank filter and fitting a diffuser in it in place of a hydor. I know it will be hugly but if it works..... We will see.
the microbubbles in the tank work better.Hey its close enough, actually its the same thing...I am basically asking which is better....adding co2 in the filter and "completely" dissolving it or an atomiser on the outflow thus filling the water column with microbubbles?