Hi all! I need some help finding a spa heater for my in-laws spa. Their pool heater has broken beyond economical repair and they only use it for the spa so they'd rather replace it with a smaller heater. The spa is about 5 foot in diameter and maybe four feet deep in the footwell. I've found this one: http://www.bestbuypoolsupply.com/product1596.html. But I'm wondering what else is out there?