Lyme disease is diagnosed clinically based on symptoms, objective physical findings (such as EM, facial palsy, or arthritis), or a history of possible exposure to infected ticks, as well as serological blood tests. The EM rash is not always a bull's eye, i.e., it can be solid red.
Rule of Thumb for Changing Filters. The rule we have followed for 18 years in the filtration industry is to change filters every 6 to 12 months. Six months is almost always optimum, especially in commercial/office settings, and twelve months is as long as you want to go no matter what.
The second most important thing you can do for you and your hot tub is to CHANGE YOUR WATER about every three to four months. We know it's a pain in the butt but the reason why most hot tub manufacturers recommend it is that no amount of chemicals can protect you completely in water that is really old and dirty.