Our 1-quart Pool and Spa Leak Sealer is an advanced formula ideal for fixing minor leaks in fiberglass pools and spas. This product has a very high pH (about 12) so when you add it to your pool or spa it takes on the pH of the water (between 7 and 8). It now no longer functions as a liquid and starts to solidify in the presence of oxygen at the site of the leak. This advanced Leak Sealer can seal leaks losing up to 1-inch of water per day. This amazing product is fast acting; usually fixing a leak within 24 hours of use. No draining of the pool or spa is required. One 1-quart bottle treats up to 15,000 gallons of water.