Hi @Geoff87 -
This is a solved problem! Checkout Sydney’s guide, as well as Kurt’s.
Keep in mind that while the Atlas scientific sensors work well, they often require (frequent) calibration and are not of the same quality as those used in (very expensive) water quality sonde’s. User’s have had success with short deployments, but I would expect a long, resident deployment to have issues with drift / accuracy, especially due to biofouling.
Kurt’s approach to waterproofing the sensors with large glands seemed to work pretty well! I’m skeptical it could handle 300m, but 50-100m is certainly possible!