DIY Recirculating Co2 Scrubber

Reef_Freak720 · Nov 20, 2023

I'd been wanting to give this a shot for a bit but finally decided to get it done after installing a Biopellet reactor a couple days ago.

Designed and 3d printed my own lid for the Reef Octopus 110
Excuse my messy stand I gotta do some cleaning for sure.

Ran the line to a cheap plastic container from Dollar General. 3d printed the bulkheads also! Pretty impressed with how those turned out honestly.

Did crack the plastic though, doh!

Here are the results from overnight last night. You can see how my ph average starts to go down after adding the biopellets. Then the big spike on an alk dose. Then after Amazon brought my Soda Lime yesterday it flat lines and starts going up. Was very happy to see these results when I woke up. I'll update later with results for the daytime peak.

Enchanted Reefs · Nov 21, 2023

Looks good! Love the DIY approach!

Reef_Freak720 · Nov 21, 2023

Safe to say it works!
Got up to 8.22 at peak yesterday and looks like it bottomed out at 8.15 starting at 2am. I anticipate the peak will be higher today.

The real test will have to be to see how high it gets when nobody is home all day.
Gotta love vacation :cool:

Steelcube · Dec 7, 2025

I know this is an old thread but do you mind sharing the 3d file for the lid?

Reef_Freak720 · Dec 7, 2025

Steelcube said:
I know this is an old thread but do you mind sharing the 3d file for the lid?

Oof I definitely dont have it anymore.
You have the same skimmer? I might be able to design something quick if I have the time and fit it on my old Reef Octopus.
Could probably design it better too depending on your space in your sump area

Steelcube · Dec 7, 2025

Reef_Freak720 said:
Oof I definitely dont have it anymore.
You have the same skimmer? I might be able to design something quick if I have the time and fit it on my old Reef Octopus.
Could probably design it better too depending on your space in your sump area

Yes, I've got the 110-INT. I was thinking about making a spacer to put between the cup and the lid but looked around for an existing model first. I've got a pretty decent amount of space in my sump. It's a waterbox 90.3 and has plenty of vertical space. The scrubber sits to the left of the tank stand.

Reef_Freak720 · Dec 7, 2025

Steelcube said:
Yes, I've got the 110-INT. I was thinking about making a spacer to put between the cup and the lid but looked around for an existing model first. I've got a pretty decent amount of space in my sump. It's a waterbox 90.3 and has plenty of vertical space. The scrubber sits to the left of the tank stand.

I'll dig my old one out and work something out. Going away for a few days.

If you dont hear back from me dont hesitate to dm/ping me to get me going lol.

Steelcube · Dec 14, 2025

I ended up making a spacer. I had a lot of trouble determining the size of the cup and lid but eventually got it. It could probably be smaller and also shorter but works so far. I also added 1/4" NPT threads to screw in fitting. I'll probably add a push to connect fitting. I'd prefer using a larger tubing size but couldn't figure out what the ID was for the skimmer air inlet hose, especially what 1/4" NPT fitting I needed, so I ended up using 1/4" airline hoses. I can't attach the file though.

Here's a link to it on tinkercad: