cfm fan + Amazon ¿?

I got a 190 cfm fan by accident and want to return it and get a 440 or better fan. I have an air-cooled 600 w dimmed to 400 w HP's as its to hot with it running 600w and the fan is pretty loud 4" going to 6 " hood to 4" filter it's a venTech combo from Amazon. It says I can exchange until the 31st but it's used,so I'm not sure. Anyone know Amazon's policy? I'm gonna see if I can look it up now.
The one I'm looking at is venTech 6" 440 cfm combo.$ 140. Anyone have something else to recommend or to say about this?

I bought this fan off of Amazon in 2011 and it's still going strong: https://smile.amazon.com/gp/product/B002JQ4K1I

somebody1701 said:

I bought this fan off of Amazon in 2011 and it's still going strong: https://smile.amazon.com/gp/product/B002JQ4K1I

Click to expand...

Can you compare the noise to a venTech?
What's the quietest fan out there?

I bought a variable speed control for it and it's very quiet at 70%. I don't have actual decibal numbers though.

nxsov180db said:

Hyper fan would be the quietest in my experience, but a furnace fan is actually even quieter than that..

Click to expand...

I'm hearing hyper fan and it looks like the most pro inline; or an iso max acoustic/airforce 2 same same . or the best hobie jobie, the solar & palau or the best for industrial wich I am not set up for would be a furnace fan.
Am I on the right track?
There are better bargains perhaps but I am sharing the bedroom with a grow and it's gotta not be heard louder then an ordinary fan outside the window there.

somebody1701 said:

I bought a variable speed control for it and it's very quiet at 70%. I don't have actual decibal numbers though.

Click to expand...

Proly quieter then the venTech but they look the same.