I just ordered and received a Petco #9902 pump, unfortunately it doesn’t appear to be adjustable according to the website.
Unless I’m missing something, there are no knobs or dials to turn anywhere on this thing. The bottom of the device has the model number AC-9902. Not sure if this is the same thing as the instructions, but the link above is EXACTLY where I ordered it from.
Rather than argue with Petco, or try to find another pump, I’m simply going to find some inline control valves I can use in order to adjust the airflow. I’ll post my results (including pictures)!! Hopefully this will make any pump a good fit for this project.