The Hagen PT1501 is the correct replacement foam kit for the following:
The PT1501 Pressure-Flo Foam for PT1500 System- 3-Pack is a foam kit for the Laguna Pressure-Flo 700 and 2500. This three pack of replacement foam filters provides crucial mechanical filtration by removing debris from pond water and keep water clean. The Laguna foam filter features super porous foam material that is durable and reliable. This water pump foam filter is easy to use and install.
PT1501 Pressure-Flo Foam for PT1500 System- 3-Pack specifications: