The AquaFX Poly-Blown Sediment Filter 20x4, 1 Micron is a crucial pre-filter designed for advanced saltwater aquarium RO/DI systems. This high-performance filter effectively removes a wide range of unwanted particulates from your source water, including sediment, silt, dirt, sand, scale, and rust particles, ensuring a cleaner input for subsequent filtration stages. Boasting a Poly-Blown Multi-Layer Gradient Design, this filter utilizes a multi-step micron rating to efficiently trap particulates, which extends filter life and helps maintain consistent water pressure. It is constructed from 100% pure thermal-bonded polypropylene, free from binders, solvents, or glue, and made from food-grade materials for high capacity and flow. Manufactured to FDA Standards, it can handle a maximum water temperature of 140F (60C) and a maximum pressure of 120PSI, rated nominally at 1 micron. This 20 x 4.5 inch filter fits all standard 20 x 4.5 inch Big Blue housings. Ideal for reef keepers employing well systems or commercial RO systems, this sediment filter is essential for protecting and prolonging the life of your expensive RO membranes and DI resin. By significantly reducing large particulate matter, it ensures the highest quality purified water for your delicate reef environment. For optimal performance, it should be replaced every 4-6 months or when a 5 PSI pressure drop is observed.