Skidooer

I too have a goplus hot tub that won't heat up. I have reset the high limit and that didn't work. So I proceeded to dismantle the puppy and I took out the whole system and removed the element. I tested it and it gave me the readings I was suppose to get and the element looks like new. I tested the highlimit and found it was still open. So I reset it again and this time it showed closed. I then removed the power and replaced it back in and I then retested the highlimit and again it showed open. So I'm anticipating my problem is the high limit. Only problem is where do I find a high limit like those. It absolutely must have the proper one to fit where it needs to so so it can detect water temperature and work like it should, to shut down the heater when the water gets too hot. I need a high limit new or used.