I was getting a slightly concerning amount of coralline on my two optical water level sensors for my ATO/AWC system. After an overnight soaking in a dilute citric acid bath (1/8 cup in 16 fl. oz. RO/DI), the coralline came off easily with a toothbrush.
Since an earlier post on how I mounted these sensors was mostly text with minimal "after"-only images, I'll try to clarify here.
Here is the tee I fabricated and super-glued the sensors to. Make sure you have your sensor spacing worked out with precision before gluing!:
Detail of the bevel I cut to dovetail with the magnet casing:
Here are a couple of views of the finished assembly:
As a preventive measure, I fabricated a couple of shades for the sensors from some black silicone tubing I had on hand. Here are the tools and materials used:
The two shades are in the first pic withe the raw tubing. Here is a close-up of one shade:
Mounted, they look like this:
Here are the shaded sensors back in the tank:
I will need to watch for at least two things: CUC entering the shades and affecting sensor accuracy and algae buildup on the inside of the shades, especially at the bottom where light still reaches. I may need to cut the shades at a 45° angle so there is no part of the bottom exposed to direct light.