Hi,
Sorry, I should have explained myself. A few things I don't like about the skimmer are:
1) Small reaction chamber -- assuming the reaction chamber is 4" tubing at 13" high, it isn't the biggest reaction chamber. Factor in the fact that it looks like the output of the pump is ~1/2 up the pipe, your reaction chamber really only is about 7" or so. I don't think that this is large enough to provide enough contact time to get all the crud out of the water.
2) I highly doubt that this skimmer can do 100US Gallons
3) I really don't like the powerhead driven venturi skimmers. I use to run a CPR Bak Pak and it did an OK job, but now I've used both Needle Wheel and Beckett style skimmers and those perform 1000x better IMO.
4) The skimmer has to be in sump (but that's a personal taste thing)
5) You get what you pay for (unless you DIY
).
These are just my reasons mind you. Hopefully some of the more experienced reefers out there will shed more light on it.