DIY CO2 scrubber

ReefDreamz · Dec 11, 2022

I made a CO2 scrubber using DI resin canisters. I wanted to add some carbon to take any impurities out of the air. I noticed its pretty hard to suck or blow air through the canister once assembled. Can these DI resin canisters not be used for air applications? Could I drill a hole in the top of the resin canister like inside the gasket to allow for more air flow?

1ocean · Dec 11, 2022

hmm. I don't know. But my guess is that DI reactors made to be used under pressure so thats why hard to get air flow. So i think your idea to drill a hole or several holes in the canister top should solve it. What does the bottom of the canister look like. If the holes on the bottom need to be drilled also then I would do that too and add foam block to the bottom and the top of the inside canister to prevent carbon falling out or getting sucked out...
I am totally into repurposing things to save cash like you...

Gtinnel · Dec 11, 2022

I always thought (possibly incorrectly) that the only difference between the co2 scrubber canisters and the di canisters was the size/type of the fittings where the hoses connect.
When you were trying to force air through them what media was in them or did you try it with them empty? If empty air flows well and it slows once the media is added then I don’t see how addding a hole in the top would help much.
I’m also curious what is in the left canister in the picture with it assembled, it doesn’t look like just one of the cartridges with media inside.

ReefDreamz · Dec 11, 2022

Gtinnel said:
I always thought (possibly incorrectly) that the only difference between the co2 scrubber canisters and the di canisters was the size/type of the fittings where the hoses connect.
When you were trying to force air through them what media was in them or did you try it with them empty? If empty air flows well and it slows once the media is added then I don’t see how addding a hole in the top would help much.
I’m also curious what is in the left canister in the picture with it assembled, it doesn’t look like just one of the cartridges with media inside.

Its not the media slowing the air flow its the DI resin cartridge. If you leave the canister empty air flows fine. If you add a DI cartridge with or without media its very hard to suck or blow air through. I tried replacing the hard foam insert in the DI cartridges with a light foam pad and its better but still kind of hard to move air through. The left canister is just filter pads with some water. CO2 media works best with moist air.

Reefer Reboot · Dec 11, 2022

You can remove the foam at the top of the media cartridge altogether as there will not be enough air flow velocity to suck up the soda lime pellets. You may also try removing the cloth screen at the bottom and replace it with something like window screen.
Just FYI, I'm running something very similar, (from an earlier post, https://www.reef2reef.com/threads/co2-scrubber-intermittent-success.835073/#post-9161023 , post #15.)
"I'll just throw in this method I have been using simply for consideration. I use a high-volume air pump which draws in fresh air from outside. From there it goes to an airline which enters the first canister and ends in an airstone deep in the canister bowl. This first canister is almost completely filled with RODI water. From there it is connected to the second cannister which is filled with soda lime. From there it is injected into the air intake of the skimmer. Kinda like a turbo charger for the skimmer. The water in the first cannister lasts about two to three weeks and the soda lime lasts about a month. Adding water is as simple as unscrewing the bowl and refilling it. No need to turn anything off. This method allows more oxygen to be added than recirculating from the skimmer cup."

(Explanation reason) The amount of air flow through the media cannister will be determined by the difference in pressure (PSID) between the inlet and the outlet of said cannister. That's where the problem lies. Depending on just the venturi, theoretically the best that could be achieved would be 14.7 PSID. The reality is that the venturi of the typical skimmer is not going to come anywhere near this. I'd be surprised if there is even 5 PSID, although I admit that I have never actually measured mine. Using an air pump increases the PSID.
Hope this helps.