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As discribed in UNESCO’s Phytoplankton Manual (published 1978) the Combined Plate Chamber allows you to look at sedimented plankton samples from a very short distance. How? Put the sample into a cylinder on top of the rectangular plexiglass plate with a thin base plate, let the fixed plankton concentrate and after sedimentation simply push the cylinder with excess liquid aside. The handling support underneath the plate will collect the extra water from the cylinder. You can now take the plate and examine the sample under an inverted microscope. Three calibrated cylinder sizes are provided with each set allowing to analyse different sample volumes.