Step 9: Water Gauge
This was fun to install as I didn't want to waste all the nice rainwater and drain the tank before I drilled a 3/4" hole in the bottom of the tank to install the angled shut-off valve. Reminded myself to only use a battery powered drill :)
I reused some 1/2 inch plastic tubing that I had left over from another application and connected it to a 3/4 inch angle valve with a shut off (which came in handy during install)
I sealed around and under all penetrations into the barrel (valve and screws) with a two part epoxy that was a water proof filler and sealer.
It is important to not completely seal the tube or the level will not change to reflect the level in the barrel.