N.P.I. Nordic Hot Tubs IMPULSE, Owner'S Manual

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UNDERSTANDING HOT WATER CHEMISTRY
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| NORDIC HOT TUBS | OWNER’S MANUAL
Several things need to be checked and adjusted regularly.
We will break things down for you in order to keep it as easy
to understand as possible. You’ll be a pro in no time, but
please contact your authorized dealer to get started. They
will know what works best for the water supply in your area.
Your dealer will be able to supply you with water test strips
to measure the items noted below. There are also drop-style
testers available if you prefer.
STEP 1: TOTAL ALKALINITY (TA)
Total Alkalinity is the best place to start. It is the measure of
the total levels of Bicarbonates, Hydroxides, Carbonites, and
other alkaline substances in the water. An easy way to think
of it is as a “buffer” for the pH. It is a measurement of the
water’s ability to resist changes to the pH level in the water.
• If the TA level is too high, the pH level will be difficult to
bring down. Either add more water to your hot tub or add
sodium bisulfate (pH/Alkalinity down).
• If the TA level is too low, the pH will fluctuate all over the
place. Erratic pH can cause scaling and corrosion prob-
lems with your tub. Add sodium carbonate (pH/Alkalinity
up) to correct.
• TA levels and range from 20-180 with the ideal TA balance
being between 80 and 120.
STEP 2: pH
pH is the measure of how acidic or alkaline your water is.
Values above 7.8 are too alkaline and values below 7.2 are
too acidic. If the pH is too high or too low, you risk damage
to your spa shell, the equipment, and the water can be
generally uncomfortable to enjoy.
• If the pH is too high (alkaline), the sanitizer will become
less effective, scale can build up on the spa shell and
equipment, the water may become cloudy, and the filter
may become plugged. You can add sodium bisulfate (pH
down) to the water to correct it.
• If the pH is too low (acidic), sanitizers will dissipate quickly,
the water may corrode equipment, and make the water
unpleasant to sit in. You can add sodium hydrogen car-
bonate (pH/alkaline up) to correct it.
• pH levels vary between 6.6 and 8.2 with between 7.2
and 7.8 being ideal.
NOTE: After adding pH up or pH down, it is important
to wait at least 2 hours before re-testing the water.
STEP 3: CALCIUM HARNESS (CH)
Calcium Hardness is the next thing to check. It is a measure
of the total amount of dissolved calcium in the water. If there
is too much dissolved calcium in the water, scale can build-
up on the shell surface and inside the equipment. If it is too
low, the water can become corrosive to the equipment.
• If the CH is too high, scale can build up on the shell
surface and inside the equipment- this can damage the
heater and pump. This is commonly referred to as “hard
water”. A generic calcium reducer will lower the CH in
the water. A stain and scale inhibitor can also help reduce
build-up.
• If your CH is too low, a general CH increaser can be add-
ed to the water.
• CH levels range from 75 to 275 on most scales and the
ideal CH balance is between 100 and 150.
STEP 4: SANITIZERS
Sanitizers (ie: Dichlor) kills bacteria, algae, and other
microscopic organisms as well as break them down for
filtration to be effective. Chlorine levels are measured
in PPM (parts per million) and occasionally need to be
“shocked” to keep the levels in check. When they are
correct, there is very little odor or irritation caused by the
spa water. Most Nordic spas will require between ¼ and ½
ounce of granular Dichlor to get started.
NOTE: Do not add sanitizer until TA, CH, and PH are
correct.
• Chlorine levels between 3.0 and 5.0 are ideal without
using an ozonator
• Chlorine levels between 2.0 and 4.0 are ideal when you
are using and ozonator.
Normal sanitation does not eliminate and filter certain forms
of contamination which ends up in the water. Sun tan lotion,
sweat, body oils, and hair spray, etc. require a little “kick”
to help get them broken down for filtration. This “kick” is
known as Shocking the water.
• Add 1 ounce of non-chlorinated shock a minimum of
once every week.
• Additional non-chlorinated shock can help clear up
cloudy water and unpleasant odors; or after heavy bather
loads
NOTE: the spa must run on high speed a minimum of
30 minutes with the cover removed whenever shock is
added. The cover can be damaged by the off-gassing
from the shock treatment.