that little skimmer actually works somewhat well but really will not pull enough to reduce water change schedules. Now if it were me I would do the sump(makes reefing sooo much easier even with small tanks) and bare minimum get a reef octo NWB-110 or a seaside aquatics cs 3.5.. they will work great for your tank and be worth the money. They will keep the tank nutrient levels lower and help alleviate water changes some. Also, should you choose to go with a bigger tank down the line, they can handle a medium bioload tank up to say a 60 gal cube or so. Now there is a bit of a price difference between the two, so IMO the reef octo is the better buy for performance, but, the seaside aquatics does offer a little better pump with the sicce. Is the better pump and cone body worth the extra $$ ? Maybe, but, it is not like the reef octo pump is not tried and true as well and the reef octo has a great semi-cone body that will do the job as well as any cone. Now a lot of folks run reef octo sro 1000's, octo NWB150s, and larger skimmers on their 40 breeders with great success, so being just a few gallons less than the 40, another option is to oversize a little and get one of those or the seaside aquatics cs 5.5 or vertex in 100. This is where it becomes hard, because for about the same cost as the slightly smaller skimmers, it is easy to jump up a size. Should you make the jump in size, now your covered to upgrade to larger tanks up in the 75 to 90 gal range and anywhere in between.