God I hate this thing:
a) its $100+ for a plastic box
b) doesn't even include filtration area (sump) cost goes up even for a DIY sump @ a reasonable return rate for a reasonable big tank return rate of 800 gph with the CS100: sump, pump = ~250-300$ (no including return plumbing)
That's a solid 350$
Oooo lookie 179$ @ bigals! For an FX5 (also 600gph)
oooo you can get TWO! thats 1200 gph... it'll only cost a little more, and it all comes in a box! No plumbing inlet, outlet, easy to clean too... god paying +100$ for a box
I would drill a hole for 10$ and plumb it for another 30$ and still save money (and yes, with proper plumbing and control of water flow (venting/drain surface on PVC) it can be DEAD quiet!
I've got 777gph (calculated) circulating off a mag-drive9.5 on a top vented stand pipe self-plumbed with tweaks and you cant even hear it drain.
So if you have money to play with and like to buy things, this plastic box is for you. Otherwise I hope you've reconsidered.
I would just get the FX5's and not waste time with a sump even.
/End Rant