Please Help...Great Lakes Hot Tub - Traverse Bay
Just bought tub and got it hooked up, taking a long time to heat up. only rasied 3 degrees in last 9 hrs.
can some help me trouble shoot??

If u got the tub second hand, there could be a problem with the heater.

Isolate all power to the spa, remove the access door.

Depending on the type of controller/heater you have, you need to inspect the heater cables for any signs of overheating.

If this is the case, you'll need to replace the board/heater or both.

Can also be a problem with the setting - some spas have an option to heat "on filtartion" or "on demand"

On demand: The spa will heat as and when it needs to in order to reach set point.
On Filtartion: The spa will only heat when it is doing it's filtration cycle in order to reduce unnecessary pump run.

Oh, also check sleep timers that be be active by default.