MAKE A SALT STRATIFICATION (HEAVY UNDERNEATH).

To make a linear salt (a.k.a. density) stratification:

1. Place unit above the tank you wish to fill.
2. Fill stirred outlet side with fresh water.
3. Fill other side with salt water.  Typically use 4 liters or less, whatever is a little more than 1/2 of what is needed.  Dissolve the salt in a separate container before filling the mixer.  Use a 20% mix and 4 liters in each chamber for the internal wave demonstration.  FILL BOTH CHAMBERS TO APPROX. THE SAME LEVEL.
4. Start stirrer.
5. Open mixing valve (let run for a few minutes)..
6. Open outlet valve slightly.  Allow a slow feed (to fill in an hour or two) into the bottom of the tank you want to stratify.
7. NOTE:  adjusting volume on each side + salt determines the stratification.  Best to measure density of the fresh side at start and at end of filling.  Then you can computer Brunt frequency  Root[ g * (density difference) / (mean density * depth of water in tank) ].

The principle is that as the experiment fills up from the fresh side, salt water leaks in from the left chamber and the saltiness of the right chamber increases almost linearly with time.

Top view of stratification maker.  Fresh water chamber is on the left.  Stirrer goes into this side.

Mixing valve (left) and filling valve (right).