Never Change Water?

[bltkmt]

I have a five year old Hot Springs Envoy (love it), and generally change the water entirely 2-3 times per year (and clean the ceramic filters). I just visited my brother in-law in Utah. He has an older CalSpas tub at his rental unit, and pays someone to maintain it. The maintenance guys says to NEVER change the water and simply maintain it via chemicals. Is this possible? Or is this because his is in Utah and mine is in CT? I would love to not have to change the water, but am not really sure...

Thanks in advance.

[chem geek]

If a spa gets regular use, you have to change the water eventually because there is a buildup of bather waste that is not oxidized. If you use the Dichlor-then-bleach method and have a spa with an ozonator then you can go longer without a water change, but never changing the water won't work with higher bather-load.

The normal water change interval that works with Dichlor-only methods is (1/9)x(Spa Size in Gallons)/(# of person-hours per day) but with Dichlor-then-bleach you get double this time. So if a spa is used infrequently, say only on weekends with one person-hour (say, 2 people for 30 minutes), then for 350 gallons this is 544 days or 1-1/2 years with the Dichlor-then-bleach method. On the other hand, if one uses the spa every day for that same bather-load (but every day), then that's 78 days or a little over 2-1/2 months. With Dichlor-only, these times would be cut in half.

[bltkmt]

Thanks. I use the Leisure Time Spa 56 Chlorinating Granules and also their alkalinity increaser, based on testing using the Hot Springs test strips.