Some bacteria will be short lived in our reef tanks. Particularly, the ones that produce enzymes for specific functions. At this time because of neglect with maintenance on a 6" DSB, I am adding bacteria once a week. If you're not having problems, a half dose once a month is good.
https://www.tlc-products.com/startsmart-complete/
This is the product that I recommend. I bought a gallon because of my large systems. It was more economical and shipping was free. While you are at the site, check on the science product information link.