The OBS3+ treats the low range and high range turbidity as if they’re two completely different things. So on Monitor My Watershed you actually have to create two different variables, one for each of the high and low range, just like you would separate temperature and depth from a CTD. I *strongly* recommend you add something to the notes field for each to remind you which is which. Once you’ve create two different variables on Monitor My Watershed, it will give you two different UUID’s.
Here’s another site with the turbidity set up for both high and low range: http://data.envirodiy.org/sites/PKCV7S/
If you really want to have only one turbidity field streaming, you can either pick one of the two or create a calculated variable that picks between the two depending on the turbidity. For most of our sites, we’ve decided to just stream the two separately.