I just talked to him. He actually has the Red Sea drop checker and it registers green all the time he says. So that blows my and your idea out the window.If you are using a Penguin 150, you are losing a lot of your CO2. My plants never pearled when I was using a 100 on my 20 gallon. When I switched to a canister (Fluval 204), I was keeping a lot more CO2 in the water. The biowheel is the culprit.