Pond Boss Forums AERATION Systems questions Simple aeration system

So, if I understand this correctly, the small unit is just to keep the water open where the big units air lines enter the water?

If thats the case, then the water depth should be pretty shallow for the standby unit diffusers, and the only question would be how many points of entry are there? (that would determine the number of diffusers needed, which would allow us to calculate the CFM needed.)

For the smaller pond units, psi is based on (roughly) 0.5 psi for every foot of water that is above the diffuser.