Check the listing for details. GLB Filter Cleanse 2lb (pack of 4). Condition: New. Listed at 99.99 USD. GLB Filter Cleanse should be used monthly during the summer and especially used after heavy pool usage, to maintain efficient filter operation. It is also important to clean your filter early in the spring to remove any winter debris and to use when closing your pool for winter. GLB Filter Cleans changes from a red color to a yellow color to indicate when your filter is clean. This product will remove all contaminants from your filter. This product is compatible with chlorine, bromine, mineral purification systems, salt water pools, ozone and biguanide sanitizers. Cleans all filter types. - Pack of 4 SHIPPING: We will do our best to ship your order based on the shipping method selected, however in some cases, your shipping method may need to be modified to meet shipping requirements based on the carrier. Our current carriers used are UPS, FedEx and USPS. Please contact us directly through the "Contact Seller" link if you need UPS, FedEx or USPS specifically for your order.