Hi, I am an unexperienced pool owner who needs to replace a dying Challenger Medium Head 1 HP pump for a 13,000 gallon pool (no spa). I thought about replacing it with a Hayward Super Pump 1 HP, but a professional recommended a Hayward TriStar 1.85 HP variable speed. It is more than twice the price of the single speed and it will hurt my finances. But if it is the best choice, I guess I'll do it. Any advice would be greatly appreciated!!