Helber Bacteria Counting Chamber

User note for Helber bacteria counting chamber, SV400 

For counting bacteria, an oil immersion lens is usually required. Many of these are computed to result in an objective-to-specimen distance of about 0.25mm. Considering that a standard #1 cover slip is ~0.17mm in thickness, the remaining minimal gap can be bridged by immersion oil.

Covers for counting chambers are polished to be perfectly flat, and since capillary action exerts suction, a very thin slip could result in an inaccurate count. ProSciTech supplies Helber with thicker than standard slips but they are suited to work with standard oil immersion lenses.