Jake, the stations we installed for you a few months ago were programmed with code that set the low voltage threshold at 3.7, which is fine in areas with lots of sun. But since your stations are more shaded, and you’re in a higher latitude, your battery will probably hover around 3.7 most of the time, so lowering your transmission cutoff threshold will keep your station online more reliably. If you look at the code example below, the command on line 370 sets the transmission cutoff voltage at 3.55v, which is probably a good level for you, though you could probably set it to 3.50 and still be fine.
https://github.com/EnviroDIY/ModularSensors/blob/master/examples/DRWI_LTE/DRWI_LTE.ino
You’ll need to update a few other parts in the code to match your individual stations. Like lines 179-191 is where you paste the UUID info from your unique logger station entry on MMW. And change the logger ID on line 47 to your unique logger serial number. And then you need to enter the unique turbidity sensor calibration equation for each station in the appropriate lines 127-129 for low range and 137-139 for high range. You can find that info in the NOTES field of the sensor parameter on the MMW station details.