Of course, it doesn't work in every case, but it has worked for me in a very high percentage of cases. I would much rather have a rat have an ototoxic reaction to gentamicin and be a bit off balance or deaf and alive than to have a dead rat, and telling people not to use gentamicin is giving many people's pets a death sentence. To date, I have still not seen a correction. With respect for gentamicin, and a little knowledge about the drug, nobody should ever be afraid of using it in under the proper circumstances. My recommendation would be to make the Tylan up daily and change the water daily.
Many antibiotics precipitate in water and are destroyed by light.
In that case, the vitamins will need to be mixed fresh every day anyway, so it is recommended to mix a smaller amount of Tylan and water when mixing it with vitamins to avoid waste.