Thanks! Given the fairly reasonable price tag on amazon, I picked up both the “large” and “big”. They arrived today and as Darrel mentioned the one with the brown disk is labeled CO2 large and the white disk is just labeled “large” and came with a plastic valve to control flow from air pump. The white disk is significantly thicker than the brown disk as well. Even though the white disk doesn’t specify that it’s specifically for co2, I think it’s worth at least trying out.
Should be interesting to run them side by side and compare the performance. Tank is finally coming on Tuesday, and I’ll try to post an update with some side by side photos later in the week.
Experience: worked in fishroom of Eddies Aquarium in Albany all through college, 20 years of keeping reef tanks, planted tanks, and dart frog vivariums.
Current/in-progress tanks: 20 gallon hi tech tank in office, 120 gallon nature/tetra aquarium at home.
Philosophy: work with what you’ve got, and make choices based on the conditions that easiest for you to maintain over time.