|Dear Spa Guy,
One of my friends was talking to me the other
night about his hot tub spa. He mentioned to me that he uses
something called the "Hamilton Index" to maintain his
water. He says the water is always clear, never smells, and it
sounds like he uses a lot less chemicals than me. I did not want to
sound ignorant, so I told him that I used it too! What the heck is
this ? A brand of chemicals, a different test kit ? Please help !
R.S., Hobbs, New Mexico
You know, when I agreed to write this column,
I figured that most of the questions would be real easy, like
"what is a pump ?". However I am beginning to see that I
have to put a lot more thought into this than I planned !
I guess our readers are pretty knowledgeable
about their spas, and you are certainly not "ignorant" to
be unaware of the Hamilton Index. As a matter of fact, I bet many of
our readers already use the Hamilton Index and don't even know it !
About 6 years ago, a California research group
was looking for a way to improve the chemical sanitization of hot
tub spa water. What they developed was named the Hamilton Index. It
involves rethinking the ways people have always been taught to care
for hot tub (or swimming pool) water chemistry.
Most of the information about spa water
chemistry is given to spa dealers by the manufacturers of spa
chemicals. This information is then taught to the spa owners.
Obviously, the chemical manufacturers would like you to use the most
chemicals possible ! With the Hamilton Index, you can actually use
less chemicals and have better sanitized spa water.
The basic concept is this - for many years,
the accepted chemical level reading for bromine was 2.0, pH was 7.4
and Alkalinity was 80. The Hamilton Index rethinks this accepted
water chemistry. By analyzing the chemical reactions down to their
molecular level, it actually turns out that these "old"
accepted chemical levels are neither the most economical nor the
best and easiest way to sanitize water.
Over the years, we at Poolandspa.com
have seen that our customers have had a lot of trouble maintaining
their pH and Alkalinty at the proper levels. If they boost the
Alkalinity level, the pH goes up too much. When they add pH Minus to
bring down the pH, the Alkalinity drops way down. They are caught in
a perpetual "Catch-22" and usually end up getting very
frustrated and just dump out and change the water. Proper use of the
Hamilton Index specifically fights this problem of pH and Alkalinity
bounce as well as cuts sanitizer use by up to 50 %.
According to the Hamilton Index, the Total
Alkalinity level should be at least 100-120 instead of floating
between 60 and 80. Remember, Alkalinity is different than pH and
must be tested with either a test strip or a 5 part dropper bottle
test kit. The benefits of running a higher Alkalinty are: less
sanitizer is needed, the pH is much more stable, there is a reduced
tendency for cloudy water and stale smell, makes maintaining other
chemical levels easier and reduces the possibility of corrosion to
metal spa parts.
The pH level should be kept between 7.6 and
8.2 instead of 7.4 to 7.6. The darker red color on most test kits is
better than the middle pink/red color. The benefits of running a
higher pH are: less sanitizer is needed, sanitizer is more stable,
less skin irritation, less chemical smell, reduces corrosion of
metal spa parts, reduces chance of algae, improves water clarity,
and higher pH is automatically "locked in" when Alkalinity
is at 100-120.
Your sanitizer level (bromine) should be 1.0
instead of 2.0. The lighter yellow color on most test kits is better
than the middle yellow color. The benefits of this are: less
sanitizer odor, less skin irritation, less inert chemical materials
building up in the water, less water foaming, less sanitizer cost.
You will quickly find
that maintaining your spa water chemistry becomes much easier, and
something that you can do only once a week, rather than every few
days. Feel free to call us if you have questions !