Onset HOBO® Bluetooth Pendant Light and Temperature Data Logger

This logger will only give you light level values in lux.  It is not a Photosynthetically Active Radiation (PAR) sensor.

This same company does make a PAR sensor that is designed to be used with their weather station loggers however it is not designed for use under water.

Here is a link to it: https://www.microdaq.com/onset-hobo-par-light-sensor.php

I'm afraid that this product isn't sensitive enough to work well for that application.  To accurately measure levels that low I'm thinking you will need to most likely look for a high accuracy light sensor and not one that is built into a data logger.  Most sensors have a scalable output that you can run into a data logger so you can still record your levels.

This logger records light levels in Lux and has a range of 0 to 167,731 lux.  The typical accuracy in direct sunlight is +/-10%.

As long as these values work for your needs the logger would be fine for your application. 

At this time this product doesn't have that capability.  The wireless connectivity of this product is intended only as a way to configure the logger and download data without having to use an interface.