Review on Pawfly Stone Bubbler Aquarium Hydroponics by Kimberly Williams

When sealed and not chipped they produce tons of microbubbles and a great air stone. Although after buying 4 packs 2 of them had broken off and had uneven black seal where it wouldn't stick. They provided prompt service to replace these 2, but then one of the 2 spares they gave me still had bad sealant - like they taped it around the hole and even after 12 hours of soaking, only air bubbles emerged right around that black sealant around . instead of pushing it through the ball's air stone. Be sure to contact the production as they will hurt you and do some quality checking before the product is "finished" before shipping. When I sealed the stones properly and didn't chip them they worked amazing but the quality was very inconsistent.