alt Hacker News> It might be that I didn’t maintain it properly and the water reservoir was building up bio film over period of time and actively distributing bacterial to my gums.
Not in any way knowledgeable on Dental Hygiene, so take this for layman's advice from someone who has used a water flosser for half a decade to positive effect: To anyone reading, please read the instructions in terms of proper usage, how to place it, etc., don't go full blast in the first few weeks and absolutely clean it according to the instructions. At least always empty the water fully and dry it out with the reservoir opened.
Not saying this is what caused your negative experience, mind you. Again, Dental is not my field (Dentists, feel free to correct me if anything I wrote is wrong), but from my understanding and reading (I did read some papers when deciding to buy my first, cause of course I do my purchasing decisions on PubMed), some peoples gums seem to be simply more sensitive [0] to water flossers, even with proper device maintenance. In the end, always clear with your dentist.