Review on Hydrofarm Active Aqua AS6: Premium Set of 12 Blue 6 Inch Air Stones by Ashley Gvozdeva

Very poor materials and workmanship. When connecting an airliner, some air connections came loose, and stones fell from the material during handling. A poor connector seal on the stone means that most of the air bubbles will escape around the connector and not travel the full length of the stone. A low-volume pump can't do anything about it, and a good high-volume pump deserves a better stone. I didn't request a refund but I wish I had. I threw away the whole box of rocks before realizing I paid almost $20 for them. Do yourself a favor and buy some quality stones, it's not.