Water quality monitoring is vital to guaranty endless water resources to the human population. In that sense, orbital remote sensing can be a significant tool for large scale monitoring. However, the retrieval of water parameters that could inform about water quality depends on the reliability of the algorithms. This work aims on testing the suitability of an algorithm for retrieving the in-situ Chla absorption peak in 676 nm (aphi(676)) as a proxy of Chla concentration for Amazon floodplain lakes. This way aphi(676) could be used as a surrogate of Chlorophyll-a (Chla) concentration. Results show that, for the receding period, aphi(676) instead of Chla can be more suitable for a better understanding of Chla dynamic in Amazon floodplain lakes. This approach also encourages the use of in-situ absorption data to support Remote Sensing retrievals of Chla.