Marineland Silicone Aquarium Sealant. Marineland Silicone Sealant is non-toxic and a 100% silicone aquarium sealant that is easy to apply and provides a long-lasting waterproof bond. Permanently flexible and does not crack or shrink Waterproof seal stops leaks Sam strength silicone used to manufacture new aquariums Non-toxic for use on fresh water and saltwater aquariums Easy to apply Available Size: 2.8 fl oz