Yes this. Curious myself.
I’m surprised that you guys didn’t know that CO2 runs high indoors. We exhale CO2 in our houses all day long. Depending on the size of your house, room, and family will depend on how high the level will be. pH in a home reef tank is directly impacted by this elevated CO2.
There are devices that measure CO2 in a home, but these are not needed because CO2 in a home is not high enough to cause CO2 retention. However, it will definitely drive your pH down which is why a lot of reefers (including myself) run our skimmer input on outside air. I’ve seen a few guys measure their houses over the years and there’s a significant difference compared to outside air. One that comes to mind was a fireman who had access to a monitor they had at work.
One guy went out of town and caught his son having a party by monitoring his pH on the Apex.
It’s easy to run at 8.4 pH. Just run a hose from your skimmer to outside and dose Kalk. I’m running 8.4 all day long. I dose 300mL saturated Kalk daily on top of my ESV B-Ionic.
