We have different views of what a professional is, I guess. At commercial level you really need to be advised by someone qualified to solve your problem. If not for the sake of your business then for the sake of your customers' safety. Engaging anonymous home brewers online is very risky, frankly. As is playing with chemicals. Sounds like you under pitched, either too few healthy yeast cells or 'enough' half-dead cells and possibly into wort that wasn't sufficiently fermentable. Believing otherwise based on assumptions won't solve your problem. How do you assess yeast quality and determine your pitching rate exactly? Dry yeast are usually half-dead at the best of times. You shouldn't just follow the instructions on the pack. As a professional you need to confirm prior to each pitching. If you want to stay in business, that is. What are you using as a fermentation vessel(s) and how do you manage temperature, pre- and post-pitching? It's not unusual for under-pitching issues to be exacerbated by poor pitching practices. What are your cleaning procedures? How do you sanitise? Due to scale and higher risks, standard home-brew procedures are not necessarily optimal for your situation. You should not be brewing like a home brewer, basically. You need to be following documented standard procedures at all times. Only then will you have a better chance of not getting problems like this. That is free advice. If you don't like the sound of it and decide to ignore it that's entirely up to you. Your best bet is to get advice from other commercial brewers. Any local to you? There are online forums for pro brewers too.