They had a booth at Seattle Boat show and they claim proprietary microbial probiotic technology to help keep both black and grey water tanks clean and reduce odors. I don't currently have any issues and can visually see my tank in the mechanical room and it looks good after being pumped. Just curious if others have had any success and if using this product once a year might be beneficial in keeping hoses and the bottom of the tank clean. They make a smaller bottle that is Marine labeled but is the same contents as larger bottle shown. Appreciate any feedback.