The removal of phosphorus (P) from agricultural runoff is essential to reduce the threat of eutrophication in bodies of water. In this study, an alternative method of applying P reactive materials (RMs) in the form of suspended reactive filters (SRFs) is presented. The SRF method enables P which has already entered a body of water to be caught. In this study, an autoclaved aerated concrete (AAC) was used as the SRFs. The experiment was carried out in a laboratory in a hydraulic block of 1 m in width and 2 m in length. Three curtains, consisting of eight suspended bags filled with the AAC, were used. The ratio of RM mass to water volume in the hydraulic block was 3:1 (g:dm3). The initial concentration of P amounted to 1.335 mg P-PO4·dm-3. The results demonstrated the successive reduction of P in the water over the experiment duration and the number of cycles in which water passed through the system of curtains. SRFs filled with AAC decreased the level of P-PO4 in the solution to 0.190 mg·dm-3. The highest removal efficiency (50% overall P reduction) was observed at the beginning of experiment, when the average unit sorption amounted to 0.192 mgP-PO4·g-1.