Fix A Leak is a blended-concentrated material designed to seal minor leaks in the plumbing. One 8 oz. bottle is effective for hot tubs and spas ranging from 250-1000 gallons (950-3785 liters). Hot tub and spa leaks can be detected by notable water loss not caused by evaporation, a wet spot on the ground, or possibly a slow drip coming out of the foam insulation. If the foam insulation surrounding the tub or spa is saturated with water the hot tub or spa has been leaking for a prolonged period of time.