Aaron: Our Coulter Counter died a number of years ago. It was too 
expensive to fix or purchase a new one. For our very basic needs, we now 
just use haemocytometer counting. That may not work for you but it has 
satisfied our needs. It has been a while but my recollection is that the 
single threshold Coulder Counter worked for us.

Good luck.

            Ron

Dr. Ronald E. Pearlman           [log in to unmask]
Associate Scientific Director
Co-ordinator, Student Outreach Programs
The Gairdner Foundation
Past President and Advisor
Royal Canadian Institute (RCI) for the Advancement of Science
University Professor Emeritus and Senior Scholar
Dept. of Biology
Director, Core Molecular Biology Facility
York University
4700 Keele St., Toronto, Ontario, Canada M3J 1P3
Phone:416-736-5241; FAX:416-736-5698

On Tue, 5 Feb 2019, Aaron Turkewitz wrote:

> We need to replace our Coulter Counter, which is the model in which you can set dual threshholds (the Z1-D).  From what I can tell, the model with a single threshold (Z1-S) should be equally good for counting Tetrahymena, but does anyone have any experience with this?
> Thanks very much
> Aaron Turkewitz
>
>