Check the listing for details. SR Aquaristik NPX Bio-Activated Polymer 200ml Aquarium Nitrate Phosphate Remover. Condition: New. Listed at 13.98 USD. SR Aquaristik NPX Bio-Activated Polymer 200ml Aquarium Nitrate Phosphate RemoverIdeal for Freshwater, Saltwater & Reef AquariumsNatural removal of nitrate and phosphatesTreats up to 50 gallons of aquarium waterContains 100% pure carbon polymersReduces aquarium maintenance and optimizes water qualityRecommended Dosage: Add (4ml) for every gallon of aquarium water or 40ml for 10 gallons. One container treats up to 50 gallons. How to: We recommend using NPX Bio-Activated Polymer in a media reactor or in a filter container that will keep the NPX Polymer in constant motion with consistent water flow. Media that becomes stuck together should be separated or removed. The use of a good protein skimmer is strongly recommended when used in a reef aquarium. How often: Keep NPX Bio-Activated Polymer quantity consistent by replacing product consumed by bacteria. Product normally lasts between 3 and 6 months. Please Note: It normally takes between 2-4 weeks for the product to become active and start naturally removing the phosphate & nitrate. To prevent the possibility of cloudy water caused by a bacteria bloom, we recommend starting out with a half dose and slowly adding product weekly until proper dosage is achieved. Click here for Material Safety Data Sheet (MSDS)RETURN POLICY: We want you to be happy with our products! If you are not 100% satisfied with your purchase, you may return it for a replacement or a refund of the full product cost. It's part of our no-risk customer guarantee! (please see the details under the Shipping & Payments tab)