I'm sharing an idea I've had for an in-line sight glass. I will use it to monitor the clarification of the wort as well as monitor run-off color. I picked up a 1/2" diameter 8" long borosilicate glass tube from McMaster yesterday for less then $10. (3723K11) I plan to insert the sight glass just after my mash tun, on the low pressure side of the pump. I'm not worried about the pressure in the glass, but I'd like to get away with a slip fit from the silicone hose. If the slip fit doesn't cut it, I'll add some stainless hose clamps. The tubing is really thick and seems to be fairly strong. The ID is a little smaller than I expected, due to the wall thickness, but since it will be on the inlet side of a throttled pump, I don't expect any issues. If I have any issues I may try the 5/8" diameter next. I'll post pics from my next batch.