Would the 180 Extra Slim be too big? It appears to be rated 105 - 198 gallons. The only reason I am asking is in case of an upgrade. It would likely be to a 180g. Is the $130 price difference worth the 65ish gallon rating more? I would be buying it new. How hard are these things to sell used if I were to upgrade and just sell the skimmer and buy another new one? Hope that makes sense. I'm extremely tired.