9
SOME TIPS ON
WATER CHEMISTRY
Your heat pump, just as any type of pool heater (gas, oil, electric, etc.), features some metal parts that can be damaged by
bad pool water chemistry. The condenser of your pool heat pump is made of a copper alloy that, as resistant as it is, is
sensitive to pH. That is why we strongly recommend testing the quality of the pool water regularly. These tests must be
made on at least a weekly basis and must at least feature the following: chlorine or bromine, pH and total alkalinity (TA).
We suggest having the pool water tested by a professional (often free of charge) once a month.
The water of the pool
or spa must be maintained within the standards included in this manual. Failure to maintain proper water
balance will void your pool heater warranty.
Chemical Products Concentration in Pool Water Standard
pH
7.2 to 7.6
Total alkalinity
80 to 120 ppm
Total hardness
200 to 400 ppm
Free chlorine
1 to 3 ppm
Chlorine stabilizer (Cyanuric acid)
40 to 100 ppm depending on regional climate
IMPORTANT:
Several components (e.g., pH, total alkalinity, calcium hardness, temperature) influence water balance,
typically measured against a standard Saturation Index (SI).Although each component has its own individual recommended
range, the individual components are weighted and combined in a mathematical function to determine whether the water
is properly balanced (SI range: +0.3 to -0.3).As a result, even if major components are within the recommended individual
ranges, but at the extreme high end of those ranges, the water may not be balanced and problems may occur.
Example:
If your pH and total alkalinity are both at the high end of their recommended ranges, scaling may occur.
This
is one of the reasons why you should have your water checked by a trained professional periodically
.
The most important factor for the durability of the pool heat pump is the pH because the capability of the water to cause
the degradation of metal is directly related to it. Total alkalinity is the measure of the capacity of water to resist pH
variation; therefore it is also very important.
How to Adjust pH
A pH range of 7.2 - 7.6 is ideal for maximum comfort and minimum chlorine demand. Always adjust total alkalinity before
adjusting pH.
Low pH (acidic water) leads to stinging eyes and corrosion of open metal fittings. Raise the pH by adding sodium
bicarbonate or soda ash. Consult your pool professional regarding which chemical is best for your situation and the
proper amount to use. Check the pH after 4 hours of circulation, adjusting as necessary to achieve the proper range.
High pH (alkaline water) leads to clouding of the water, scaling and reduces the amount of active chlorine. This means
algae and germs can grow. Lower the pH by adding muriatic acid to the pool water. The acid demand indicated by your
4-in-1 test kit will show the amount of acid to use.
If your pH remains inconsistent, check your total alkalinity.
Total Alkalinity Affects pH
Total alkalinity is a measure of the alkaline chemicals in your pool water (eg. Bicarbonates, carbonates, and hydroxides). It
can be thought of as the buffering system necessary to control pH. Low alkalinity can be compared to weak shock
absorbers on a car, allowing pH to fluctuate.The pH will be difficult to maintain and staining of pool surfaces may occur
when total alkalinity is too low.
Total alkalinity should be in the range of 80 - 120 ppm.Total alkalinity is often confused with pH, which it affects.
To raise total alkalinity, add pH buffer (sodium bicarbonate) at the rate shown in the manufacturers instructions to achieve
a reading in the 80 - 120 ppm range. 1.5 lbs. of sodium bicarbonate raises 10,000 gallons of pool water by 10 ppm.
To lower the total alkalinity, use muriatic acid. The acid demand chart in your 4-in-1 test kit will indicate the necessary
amount to add. Adjust as needed until the reading (taken at least 24 hours later) is in the 80-120 ppm range. Once the
total alkalinity is correct, you may need to adjust pH.