I also just bought a 57w as well and it came with a barb fitting, power supply and unit. There was no reducer bushing. At all. Seems odd not to be able to use the unit right out of the box? I emailed them and they are going to send the reducer bushing. Did your come with one? What was in your box?Just a heads up, Aqua UV come with 2” slip union bulkheads. You can buy the reducing bushing to your desired plumbing size, then It’s just a slip straight or 90 degree barbed fitting for connection to hoses.
I just picked up a Aqua UV 57w and am impressed with the build quality and design. It’s going to be easy to maintain with the unions. It can also be plumbed vertically or horizontally with unions facing up.
Cool idea on the flow rates if you can have it be automated with a dc pump and controller.