liquid color-matching demo ends up siphoning due to lack of tubing seal within peristaltic pump

[sgbaird]

Ended up having a lot of the blue dye leak out into the waste container due to this. Some options:

• Leave it be, but make a note of it (i.e., instructions to close the valves when not in use)
• Replace with higher quality pumps that advertise no siphoning
• Add on/off valves prior to the peristaltic pumps or at exit points