[dipan]

I've been assembling a Rainbow Lifegard filter system for a new 110g planted tank that I don't have yet. I was planning on directing the CO2 into the inline mechanical filter. Here's a link to a MarineDepot exploded pic of it:

Rainbow Lifegard Single Mechanical Inline filter

I was going to drill the cap just off center and add a 1/8" barb fitting to route the CO2 through. This would put the CO2 on the outside of the pleated filter. It would have to go through the pleated filter and some biomedia in the center of the filter (black stuff in the drawing) in order to go down and out of the filter and into the next inline assembly. Space is really tight and I was hoping this would work OK. Any thoughts? The only other option is that I can run the CO2 into the filter intake. I was hoping to avoid that in order to avoid any kind of added noise. I'm not sure if it would add noise, but I suspect that it might.

 

[dipan]

Well I did this, just in case anyone else is considering it. It seems to work well. I can get "green" on a drop checker with both 4 and 5 dKH water without a problem. There's an intermittent slight gurgling sound, presumably as a small amount of CO2 gets pushed through the pleats, but CO2 dissolution is complete or near complete as no bubbles are seen coming out of the lily pipe ...