As my Glowforge filter is due 6 months after the Glowforge and I do not want to wait an extra 6 months for the Glowforge and I need to do something as pumping outside did not seem like an option I took the suggestion of others and bought the one on Amazon for $700 (after tax).
The trouble with buying from a picture is that you can totally miss the scale of a thing. Worried it would be too small for the job, it turns out not to be the problem I was expecting.
The intake (the black circle) is ten inches, and the exhaust is 5 and it will do up to 500cfm.
I am going to try to make it do enough of a job not to need the much more elegant Glowforge one, but will not be rejecting it until I am sure this is an at least equal way to go. Otherwise I may just have the cleanest household air in the neighborhood