It's hard for me to give a completely accurate opinion on noise because there are too many tanks together but it seems pretty quiet with the way the water exits it, as long as your tank is filled up all the way.
I have this same filter I got with a 20 gal kit. Do you know where I can get a filter intake valve, mine didn't come with one. I just lost a shrimp, fish, and a frog to my filter sucking them in.
I wonder why they wouldn’t have a valve in the kit version? I doubt you could get one but if you have delicate or small creatures, then I would recommend a coarse sponge over the intake.
The main concern is if you have fish or inverts that might jump/crawl out. The next concern is evaporation. So it’s good to cover as much of the top of the tank as you can, if possible.
I had the same problem. I had to really push the inlet tube down to get my water flowing, but it never “clicked” into place like it did in this video. My filter is making little hissing noises so hopefully I did everything correct. Thanks for this video, it was way better than the paper instructions!