Thank you for the phenomenal knowledge.

I am trying to link to some pictures in FLickr, and as the above shows, they are not doing so correctly.

Anyway, I have given the full links below for two pictures of the control room.

Photo one:
[www.flickr.com]

Photo two:
[www.flickr.com]

In these images, I can see marked scales next to perforated metal covers.
Next to these scales (2,3,5,8) I do not see any liquid columns. Are these liquid columns under the perforated metal covers to prevent injury if the glass cracks ? What are the units on the scales ? Are all the four scales showing trim tank levels ?
Many thanks

Pras