On a 15k pool, the minimum recommended filter size is 110 sq-ft but I would double that to minimize cleaning frequency. The combo unit with that size filter and a two speed pump is the PNCC0200OP2160 which also has a standard plug. The pump that comes with the unit is labeled a 2 HP but in fact it has the same head curve as the 1 1/2 HP pump. Also the OptiFlo pump series is a pretty small pump as pumps go so don't get too concerned with the label HP.