Joey,
What is the length and diameter of the airline from your compressor location to the pond shore?
Then, what is the length, size and depth of the line from the pond shore to the location of the diffuser(s).
What type of diffuser do you plan on using? Do you plan on having multiple diffuser locations or just one?
The drop Russ mentioned was 0.16 Psi/100' of 1/2 " tubing. If you upsize your tubing to 3/4", the pressure loss is only 0.03/100' of tubing.
