Tetratec Whisper air pumps

[MyraVan]

Hi All-

I ordered a Tetratec Whisper APS50 and received a Tetratec Whisper AP100 instead. This is their older model, but pumps more air. Now I only want a low air flow, so the ability to pump more air isn't needed, but I can deal with it as long as I can turn down the airflow. The AP100 has the two main things I was looking for: adjustable air flow and quiet operation, and as long as the airflow can be turned down quite low, and as long as the older model is still quite quiet, I'll just keep the one I got. But if the new models are much quieter, or if the airflow on the older model really can't be adjusted down very much, I'll return it to get the one I ordered.

Any opinions on these two models?