Swimming Pool Water Chemistry For The Pool Guy (Part 3) Total Alkalinity
Pool Water Chemistry Total Alkalinity
We have discussed the chlorine and the pH level of a pool in the first two parts. In this article, we will discuss the alkalinity in the water. How it is related to pH, how we can we lower or raise them both to maintain the proper level? First, let just discuss what alkalinity is all about.
What is alkalinity?
Primarily when we talk about the alkalinity, we usually refer to the measure of the capacity of water to neutralize the acid. The alkalinity plays a significant role as a buffer to not only maintain the level of pH in the water but also to protect all forms of life within the water.
You will hear a lot of pool guys talk about pH bounce and here is the key thing about alkalinity and how it relates to us pool guys. It prevents the pH from bouncing up and down. If your alkalinity is low and you add acid to the water the water the pH might be at an 8, but once you add the acid, even in small doses, it will drop the pH level to dangerously low levels.
Why is it dangerous to have a low pH? See below. Damages of a low pH level.
It will do the same if your pH is low and you add soda ash to raise your pH level. It will bounce really high.
How are alkalinity and pH interrelated?
So what is the relation between water pH and alkalinity? Think about your high school chemistry class and remember the numbered scale of pH ranging from 0 to 14. On the scale, we take seven as the completely neutral and the desired level of pH of the water. (In swimming pools the ideal pH is 7.4 ppm).
Alkalinity or more precisely the total alkalinity of water is the measure the number of alkaline substances in the water, measured in parts per million (PPM). There is an extremely close relationship exist between alkalinity and the pH of water.
Alkalinity act as a buffer or stabilizer to normalize the pH level in the water. It plays an indispensable role in the inhibition of pH bounce. Since pools are mostly in open places, there are higher chances of substances entering the water and disturbing the natural pH level of water? Some of the factors which can alter the level of pH include rain, massive swimmers traffic to the pool, leaves and shocking the pool, etc.
How to maintain the level of alkalinity and pH in water?
Alkalinity is known as the capacity of water to neutralize the acids. This ability comes from the contents of the stream, including carbonate, bicarbonates, and hydroxides. While on the other hand, pH is the expression of the intensity of acidic or basic condition of the water. However, here is the catch, the water does not need to be highly basic to have the high alkalinity.
However, the problem or confusion may arise in the use of various chemicals to maintain the level of both in water. How can the pH and alkalinity of water both be at a proper level to enhance the quality of water? So here the easy way is to adopt the below-mentioned technique.
To Increase the lower level of both we need to add sodium bicarbonate, also known in our industry as Baking Soda, to the pool. To raise the Alkalinity, you will need to use Baking Soda. Similarly, to lower the level of both we may use muriatic acid.
Note that Soda Ash is used to increase the pH level and not Alkalinity.
Damages of low & high pH level
So what would be the result of low pH level and a high pH level of water?
- Low pH:
- It may prove damaging to the human body. The low pH may cause the symptoms of red eyes, itchy skin, rash and damage the overall health of hair structure.
- Low pH means high acidic nature of water, so all your metal accessories are going to corrode if it gets in contact with such water.
- The corrosion of metals may have a considerable impact if you have a pool heater. The copper lining of the heater may get off entirely because of such acidic water and may cause a burden to your pocket in repairing or replacing the heater
- High pH:
- Scaling/calcium build up on the pool surface and tile.
- Cloudy Water
- Burning of eyes and nose
- Clogging of the filter
- Another most damaging effect of high pH is the impact it has on your pocket. Generally, with the higher pH level, the effectiveness of chlorine diminishes. So, if you are using chlorine for cleaning & disinfecting purpose, then a high pH level will hit your pocket by sabotaging the desired results.