We bought a hot tub off a friend. He told us it was called an Aqua set and that it is around 15 years old. It works fine except it wont get any hotter then 90 degrees? I cant find any hot tub sites that even has a hot tub like mine or with any names like mine. I have the following information that could help.

Model no. st 650-rlp
serial no. 87-04-154-f
volts 120/240
amps 20/30-50
PH 1
HZ 60
Spa tech, inc.

The cover says Spa-tech the function box says Aqua-set.
I have a picture of it, if you need any other info or pictures let me know please help. Thank you
URL- http://tinypic.com/view.php?pic=24lkcqa&s=4
Direct link- http://i33.tinypic.com/24lkcqa.jpg

My husband can repair anything thats needed to be fixed I am just looking to find out what brand it it. If I have a repair man come I will have to pay him just to find out its brand? Thanks anyway