Ascidians can be used as indicators of ocean pollution. Microcosmus sulcata concentrates heavy metals cobalt, zinc, chromium and selenium, and Ciona intestinalis indicators iron build-up. Other species accumulate scandium, antimony and some other harmful pollutants.
The stirrer located on Hisim's Home Page does not work unless some modifications are made.
The reason that it does not work is the stirrer is designed for small vessels, and a kalk reactor is not that small (anywhere from 1 to 4 gallons).
The reactor built by KW contained 2.1 gallons, and the 9V, 300mA transformer did not have enough power to provide the torque to the stirrer bar.
This was replaced with a 9V, 800mA transformer and it works fine.
But the additional amperage causes the motor to run hot, which in turn melts the hot melt glue.
Therefore 5 minute epoxy resin or a similar alternative must be used to mount the motor.
Additionally the potentiometer is not required.
Hence here are the modifications that should be added:
Use a 9V, 800mA transformer for 1-2.3 gallons.
Use a 9V, 1.3mA transformer for 2.4-4 gallons.
Note: make sure the motor can handle this amount of amperage.
Omit the potentiometer.
Use an epoxy resin glue to mount the motor.
Helpful hints:
Make sure the magnet purchased for the magnetic stirrer does not have opposing forces.
The first magnet I purchased pushed the stir bar away at one end while it attacted it to the other.
The stir bar should be attracted to the entire surface of the magnet.
The project box must be made out of plastic.
The box I first tried to use had an aluminum top.
This metal top somehow interfered with the motor and made it spin very slowly.
Aluminum is not magnetic, it must interfere with some sort of electrical field.
