I am using the DJ50 as my diffuser for the past 6 months. But I am using a Pressurized CO2 seup. I think you are using DJ's air mixing mechanism to inject CO2. So when there is nore CO2 DJ50 will try to blow everything. But I drilled a small hole near the water intake and injectig CO2 in it. Try it you may get good results. Dominic Ҷ2)Ehztk*Zږb^i