Remote sensing reflectance (Rrs) and concurrent chlorophyll-a (Chl) concentration were measured from August 2007 to September 2008 in two pools (Furong Pool and XMU Reservoir) in Xiamen, Fujian. During most of the time, the measured Rrs spectra for Chl ranging between 6 to 322mg/m³ show a prominent secondary peak in the far-red region of the spectrum. This is not from fluorescence alone, but appears to be caused by the red edge. Following the estimation of MODIS Fluorescence line height (FLH), we defined a red edge height (REH) during 705 and 710nm. It was found that REH was highly correlated with Chl. The relation functions are REH=0.016lg(chl)-7.8×10^-6(R2=0.79, n=41) in the Furong Pool, and REH=0.0001chl+0.0002 (R2=0.74, n=32) in the XMU Reservoir. Our results suggest that the red edge may provide a good tool for researching and management in order to study and monitor the algal blooms in waters where there are dense suspensions of algal cells.