I actually just bought this one, it works well, I have phosguard in it at the moment. I will say this is the larger one that can do from 50 to 200 and is 5.5 inch Dia but I have a 120gal and its working amazing. The reactor itself is nice so far, and would work great as for cheto being it has a 5.5 in dia and is 32in tall. goes well on the outside of the refugium without taking up room within, but if you dont want one that big they have one from the same place but is a 2.4 inch dia...you really cant beat the price for how well this thing works........oh oh one thing though, The one main complaint youll see it the pump need to be stronger....I agree to this. I have a brandnew power head 175gph that I hooked to it instead of the 150gph it came with. I'm actually going to add a 200+ gph pump to it here soon, just all matter what your running through it. Im running PhosGuard through it now and the 175 gph is just fine with it.