I would have to say no. Even though I do have customers that tell me their periodontal pocket depths check fine just from using the Hydro Floss alone and that they don't use regular floss, I would not suggest that you stop regular flossing or brushing. Keep doing both.
Anything you can do to disrupt plaque on a consistent (daily) basis is beneficial to your dental health maintenance and control. Brushing, flossing, and many other tools exist. Consistent use of those tools is going to provide you the best home care between your regular office visits. What you do at home is of the utmost importance. One a layer of plaque is intact for about 24 hours or so, the bacteria underneath can grow to dangerous proportions. They can then secrete enough acidic toxins that they can begin to do damage.
Why not make things better? I would keep doing both regular brushing and flossing as well as anything else your hygienist or dentist recommends. But, if your periodontal pocket depths are still out of control - anything above 3mm, then adding the Hydro Floss would be a logical thing to do.
Gum disease is the number one cause of tooth loss. Your most objective indicator is those periodontal pocket depths. These measurements should be taken on every single office visit. If your dental office is not automatically doing that and telling you the results, then you should ask them to do so. They should be doing it and it is important that you know what those numbers are.
In addition, many Hydro Floss users tell me about the nice clean feeling they have after using the Hydro Floss. They don't want to give that up!
Read more about the Hydro Floss
PS: Free White Paper: How to Stop Gum Disease In 4 Easy Steps
* I speak in general terms only here. Specific questions about your unique dental health situation should be directed to your dentist or periodontist.