Quote Originally Posted by bbc
the P.M-(AP+40) has 5/8"in output and the air ston`s are 1/4"in.....? ?
And not all air stones are 1/4".
Opie Yutts Reviewed by Opie Yutts on . Best Air Pump (AP-40) Thanks Opie Just got my pondmaster ap-40 air pump and man is it quiet and puts out some serious air. I run a 6 bucket DWC that I had a mid grade air pump ($50 bucks of ebay, you can see the old one in teh pics) but it was really loud and the air pressure sucked when I had (4) 4" and (2) 5" round stones. Now that I have hooked up the ap-40 the a pressure is great and I even added (3) 4" stones for the res and I have plugged 5 ports of the 12. This pump is whisper quite, my total noise dropped 50% from my Rating: 5