http://www.fish-forums.com/board/viewtopic.php?t=861&highlight=bubble+counter

Well I get a bunch of emails about what our bubble counter is so i figured since one competitors "webmaster" is saying people who sell it are trying to rip you off, I would post some info about it and why it is better than water.

1. The fluid we use is a much thicker solution which makes it much easier to count the bubbles in the viscous fluid.

2. It does not evaporate like regular water will. ( meaning yes there is some evaporation but i have been running the same fluid in mine for over a year.

3. It also will not grow algae in it like water can . Many people do whoever used distilled water and such to decrease the nutrients that may cause algea growth when using water in a bubble counter.

A suggestion when using bubble counter fluid.
Only fill the unit 1/2 of the way full.