It seems so simple. Fill the hot tub with water, turn it on, and, shortly thereafter, enjoy the soothing benefits of the hot tub.
But
there’s more to hot tub use than that. Making sure the water is clean is key to
preserving the benefits of the hot tub. The pH level of the water is critical
to that cleanliness. By measuring the pH level of your hot
tub frequently,
you can ensure your hot tub remains safe for years of comfort.
What Should the pH Level Be?
The pH level indicates how acidic or alkaline
something is.
Measured on a scale of 0 to 14, a low pH (0-6) means the liquid is an acid;
lemon juice has a pH of 2. A pH of 8 or higher indicates a base—ammonia has a
pH of 12. Finally, a pH of 7 means it’s neutral—milk and water have a pH of 7.
The safe pH range for a hot tub is between 7.2 and 7.8—very
slightly alkaline. At this pH, chlorine in the water will work effectively to
keep the water clean, and, therefore, not harmful to you. Minerals in the water
and sanitizers you add all affect the pH level; you should check it twice per
week.
Harm from Low pH Levels
If the water in the hot tub is
acidic, things can go wrong quickly. The acid will etch or corrode any metal it
contacts. The heater is made of metal, as are many of the fittings. The hot tub
walls may crack or delaminate. Sanitizers will be less effective.
The people
using the hot tub will also notice itchy and dry skin, as well as irritated
eyes. While the pH in a hot tub will rarely,
if ever, get to dangerous levels, itchiness and irritation take away from the
enjoyment of the hot tub. Low pH may also harm your bathing suits as the acid
wears away the fabric.
Chlorine
is crucial to keeping the water in a hot tub safe. Chorine works best in a slightly acid environment. Its effectiveness is at 97%, with
a pH of 6. That level of acidity, however, would lead to the itchy skin and eye
irritation noted previously.
It is
worth noting that everything which goes into the water will affect the pH
level, including the humans enjoying the hot tub. The pH of human skin is 5.5, which means we lower the pH of
the hot tub each time we enjoy it.
Harm from High pH Levels
The hot
tub also has problems from high pH levels. A pH of 7.9 or higher means the
water is alkaline and can lead to cloudy
water and scaling of the pool’s parts. The cloudy water is more an aesthetic
harm than a danger to safety, but scaling is damage to the tub.
High pH
values also affect the effectiveness of chlorine. A pH level of 8 means that
chlorine is barely 20% effective and, when pH reaches 8.5, chlorine’s
effectiveness is well under 10%. Chlorine, of course, is the most commonly used
disinfectant for water.
Contaminated
water can cause a variety of illnesses, largely because of bacteria. Most of
these illnesses lead to gastrointestinal upsets, including nausea, stomach
cramps, diarrhea, and vomiting. While these upsets will rarely be long-term (or
fatal), they certainly can put a damper on your enjoyment of the hot tub.
Changing the pH to the Proper Range
Keeping
the pH of your hot tub within the recommended range of 7.4-7.8 will ensure the
hot tub is safe and enjoyable. The first step is, of course, checking the pH and alkalinity frequently. As a
rule, check it twice per week.
If you
notice cloudy water, you are probably noticing a symptom of high alkalinity and
pH. You should test for alkalinity first. The level should be between 80 and
120 parts per million (ppm). Then, check the pH. If it is over 7.8, you will
need to address it as well.
You should
focus on the total alkalinity first. The chemicals most frequently used are
sodium bisulfate or muriatic acid. Follow the instructions from your hot tub manufacturer and the product you use. Use a
plastic bucket ¾ filled with water from the tub, and add the acid; the water
should be in the bucket first. With the hot tub running, gradually add the
contents of the bucket to the tub.
The water
should circulate for 3-6 hours, and then
check for alkalinity and pH again. The pH level follows alkalinity—check again
if the alkalinity is in range, but the pH
is not.
If the
water has a low pH, you also need to measure alkalinity. The most commonly used chemical
for raising alkalinity—sodium bicarbonate or baking soda—will not raise the pH
by much. Sodium carbonate will affect both measurements.
Enjoy the Tub
pH levels
outside the recommended range do not mean the hot tub is unsafe. You do need to
address them, however, before things get worse.
Checking and treating the water is easy and, when this process becomes part of your household routine, it will ensure years of enjoyment of your hot tub.
