I got 3 of the 404B's when I got a big tank (one went on an old 55G that needed more circulation).
They aren't quite silent but they are quiet, LOTS (I mean LOTS) of room for media.
The 404B actually moves about 270 gph
, though rated at something like 525. I think all manufacturers lie about flow rate, I know Fluval does, my 306B is nowhere near its rated flow either.
My point is buy one bigger than you think you need. Or buy two if you have a larger tank. Especially since they are cheap.
But so far they do exactly what I wanted. The inlet/outlet stuff is a bit small and cheap, but workable. On 2 of the 3 I ended up making my own intake and outlet spray bar from PVC
because I wanted something special, but the 3rd has their stock stuff and it works OK.
But quite pleased with the overall filters. They are VERY easy to clean (though the 404B is pretty heavy full of water). Their connection point is recessed, so I do not spill any water when I disconnect (unlike fluval which always squirts out about a quarter cup or so). The pump itself is easily accessed to clean.
There are no bells and whistles, the manual stinks, and you'll have to make or buy media for it, most do not deliver any with it. But I bought a couple liters of Matrix, and some bulk sheet media and cut out my own. Works fine, and dirt cheap (well, not the matrix, but that lasts forever).
I have no idea if the UV
actually does anything -- it glows, but it's pretty small for the (even lower real) flow rate.
I have no regrets.