Pond Boss Forums AERATION Systems questions Roll-your-own aeration system (pics)

I have a question. What size Medo should i go with for a pond no more than a 1/4 acre about 6' deep? Looks like the 120 may be too large. I am thinking in line of an 100 or an 80 and using no more than 2 9" discs . Hope I am not hijacking your post. Thanks.