Mine has been running 24 since this post and I love how quite it is. I am not sure if GH pump is the same as the one I had was (you can see it in the pictures on floor between the buckets) and no matter what pump I have tried, they all have been loud until this one. Now my fan (4" vortec) and a breeze fan for the plants are the loudest things I have. The AP40 is so quite, it actually might make more noise with the bubbles than the pump. I have also noticed better root growth right after I put it in, my old pump could not run 6 5" round air stones, this one runs that many and 2 14" long stones for res and controller (water level)and I am only using 8 of the 12 ports for air. I found my on ebay for an awesome deal, It was less than 100 shipped.
fosomker Reviewed by fosomker 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