Co2 Scrubber/Skimmer Size

[bcarl77]

I have a 17 gallon tank with a DIY Co2 Scrubber and Reef Octopus skimmer NS80. The co2 skimmer was able to raise pH about ~.1. I have excess Co2 in my apartment (7.5 aerated insider, 8.2 outside). Would a larger HOB skimmer help make the scrubber more effective??

[Tripod1404]

Is you tank covered or have a lid? If not, CO2 will still solubilize in water through the water surface. If that is the case, CO2 scrubbed from the skimmer inlet air will have a minor effect on pH, unless you have a over-sized skimmer that still contributes for the majority of gas exchange.

Chemically speaking, air free of CO2 passing through the skimmer will strip CO2 from the water. But equilibrium would still favor most solubilized CO2 staying in water, so large volumes of air needs to pass through the water. Again this needs a oversized skimmer.

Btw did you add small amount of water to the soda lime before connecting it to the skimmer. Dry sodalime does not absorb much CO2, especially if humidity is low.

[bertoni]

A bigger skimmer might help. That's hard to predict, though. I agree that working on trying to make the scrubber more effective would be a cheaper way to get started on the problem.