I use a nano diffusor in my tank and its fine, just as long you pump enough CO2 through it and distribute it evenly around the tank you won't have any problems. Only a very small portion of the disc lets out CO2 bubbles anyway no matter how big it is. I have mine just below the Koralia 1 powerhead which sends the bubbles all over the place and keeps my drop checker on the yellowish side.glenn said:that looks to me like the rhinox 1000 or possibly the 2000 which will not be efficient for diffusing enough co2 in your tank as the rhinox 1000 is for tanks around 60-100L and the 2000 for tanks 20-40 gallons. you what to be looking at a rhinox 5000.