Co2 Scrubber?

[tmccaff]

I got a bulk reef supply co2 scrubber. Which one do I use In or Out side on canister for hooking it up to the skimmer?

 

[codycolina707]

I got a bulk reef supply co2 scrubber. Which one do I use In or Out side on canister for hooking it up to the skimmer?

Side with arrow pointing up should be fresh air Side with arrow pointing down should be hooked to skimmer

 

[tzabor10]

It will work either way but if you are looking at it with the back facing away from you, the in port is on the left.