The SM200 is a great skimmer but the minimum recommended display size is a heavily stocked 210 gallon display. A better choice for your tank would have been the Double Cone 180. While the SM200 will work, it's way too big and you will need to run it really wet in order to keep it remotely consistent. The issue is the neck diameter is sized relative to the expected load and you will never have enough load in that display to generate enough dissolved organics (DOC's) to maintain enough consistent foam to fill the neck. If you had the skimmer dialed in properly, the skimmer will produce for a couple days and reduce the DOC's and then idle along while the DOC's build back up. The end result is your dissolved organics will be going up and down instead of staying consistently low.
My suggestion (if you intend to keep this skimmer) would be to run the pump at about 28 watts and raise the water level in your sump (with the wedge pipe wide open) until you get the line where the bubbles turn to foam up about 1/2" above the collar where the neck threads to the body. Your probably going to end up between 9-9.5" of sump depth. From there you can use the wedge pipe to raise the foam level even higher until you find a point where it's producing reasonably consistently. The only downside is that your skimmer will overflow easier due to changes in the water and or slight plugging of the Venturi due to salt creep.
With these skimmers being so conservately rated, they are best being properly sized. The idea is that you're better off having a properly sized skimmer that works consistently hard than an oversized skimmer that hardly has to work and is inconsistent as a result.
