Check the listing for details. EXO TERRA FX 200 TURTLE FILTER DUAL CARBON PADS - 2 PACK x 2 - 4 PADS. Condition: New. Listed at 8.09 USD. EXO TERRA FX 200 TURTLE FILTER DUAL CARBON PADS - 2 PACK x 2 - 4 PADS The Exo Terra FX 200 Turtle Filter Dual Carbon Pads are replacement carbon pads designed for use with the Exo Terra Turtle Filter FX-200 (model PT3630). Each pack contains two replacement carbon pads, and it seems you have purchased two packs, resulting in a total of four pads. The main functions of these carbon pads are as follows: Removal of Heavy Metals and Organic Contaminants: The carbon pads are effective at removing heavy metals, organic contaminants, and other pollutants from the water. These substances can be harmful to turtles and other aquatic organisms, so removing them helps maintain a healthier environment for the turtles. Elimination of Discolorations: The carbon pads also play a role in eliminating discolorations in the water. This helps to keep the water clear and visually appealing. Phosphate Level Maintenance: One of the benefits of these carbon pads is that they do not raise phosphate levels. High phosphate levels in aquarium water can lead to issues such as excessive algae growth, so it's beneficial to use a filter that helps maintain proper phosphate levels. In summary, these Exo Terra FX 200 Turtle Filter Dual Carbon Pads are essential for the proper functioning of the Exo Terra Turtle Filter FX-200, and they play a significant role in maintaining water quality for your turtles by removing harmful substances and keeping the water clear. Remember to replace the carbon pads regularly, as their efficiency decreases over time and continued use of old pads may not yield the desired filtration results.