The Eight Components of Balanced Water

 

 

The components of balanced water:

1. Calcium Hardness
2. Alkalinity
3. pH
4. Cyanuric Acid
5. Total Dissolved Solids (TDS)
6. Phosphates
7. Chlorine 
8. Temperature

 

The easiest way to understand each chemical and how it factors into water balance is to use a dosing calculator. Orenda has a great calculator here. Orenda also makes great chemicals that are professional strength and are available here.

 

I always recommend keeping a spreadsheet with columns for your chemistry readings and rows for the chemicals you add to keep as a reference for the future.

 

First a couple of things to consider...

 

Your fill water and what's in it. Knowing what you fill your pool with is just as important to know and understand as the eight components of balanced water. Determining if it is soft or hard will help you understand why your chemistry may or may not change quickly after you add a lot of water in the summer. You should also be cognizant if you get rainfall in abundance which can alter pH and alkalinity, as well as wash iron and phosphates into the water.

 

What you use for sanitizer and shock. The type of sanitizer you use is important as some are acidic and contain cyanuric acid (stabilizer) and / or calcium. Salt water pools have unique balance issues that require a different understanding.

 

Calcium hardness determines whether water is soft and aggressive or hard and scaling. Ideal calcium hardness is 150 to 250 ppm, with the maximum at 800 ppm. Hardness below 150 ppm is considered soft water and above 400 ppm is considered hard water. Think of hardness as a beast that is hungry. If it has an empty stomach, low hardness, it wants to eat something to get nourished. What it wants is something easy to digest like pool plaster, liners and soft metals like copper heat exchangers. If the beast has been fed too much it becomes heavy and wants to shed some pounds. This would be scaling. Calcium hardness is pretty stable and doesn't change radically. It is most affected by water splash out and the use of calcium hypochlorite chlorine in the form of powder or granular. If you have high calcium in your fill water you will need to "compensate" with the alkalinity and pH in order to balance your water.

 

Increase calcium hardness (if your water is soft) with the use of a granular or powder form of calcium chloride.

 

Decrease calcium hardness (if you water is too hard) by draining water from the pool. 

 

Alkalinity is water's ability to buffer acid. pH is the measure of how acidic water is. Together, alkalinity and pH are THE balance that you will test and adjust on a regular basis. Think of alkalinity as a balance beam and pH as what you do to each side to keep it level. pH is measured on a scale from 0 to 14. 0 to 7 is the acidic side and 7 to 14 is the basic side. Our body's natural chemistry is about 7.2 to 7.8. This is also the zone where chemicals work best, so keeping the balance on the basic side is your goal. Ideal water alkalinity is 100 to 120 ppm. You'll want to keep the water alkalinity at 100 to 120 ppm. Once you get alkalinity in this ideal range keeping it there is easy if you check your chemistry often. Be mindful that replenishing water from splash out, as well as torrential rains can alter alkalinity quickly.

 

When pH falls under 7 water starts to sway the balance to the acidic side. If yous alkalinity is below 80 ppm and the pH is under 7 you get into the danger zone. As alkalinity decreases, the water's  ability to absorb acid declines. In order to get the pH balance back you need to increase the alkalinity. Once the alkalinity gets back to the 100 to 120 ppm range the more stable pH will be. Don’t be fooled by a high pH with a low alkalinity. You MUST balance alkalinity first.

 

Low calcium hardness with low alkalinity and low pH creates a very hungry monster. This situation will etch plaster, bleach color from liners and dissolve heat exchangers in heaters. Swimmers will complain about itchy skin and irritated eyes. Shut down the pool until you get the water balanced.

 

To learn more, including how to raise and lower your pH and alkalinity, check out our article: How to Balance Your Pool or Spa pH Level.

 

Recommended readings for Cyanuric Acid (CYA) is 30 to 50 ppm. Stabilizer protects chlorine from the sun. When stabilizer reaches toward 100 ppm it can have an effect on alkalinity. This means if you have a stabilizer reading of 100 ppm and an alkalinity of 100 ppm, the actual alkalinity is 70 ppm. Your alkalinity test will state 100 ppm but it is actually 70 ppm. This situation creates aggressive water. CYA or stabilizer is a hidden chemical in stabilized chlorine products such as trichlor tablets, dichlor powder and granular shocks. The belief that more stabilizer protects chlorine better is not accurate.

 

To reduce CYA / stabilizer you must drain the pool. Hard water with high cyanuric acid is an indication to drain the pool and start fresh.

 

TDS or Total Dissolved Solids is all the “stuff” that is dissolved in solution. While calcium can be a large component, organics, inorganics, cyanuric acid, sanitizer and phosphates can be contributors. A low TDS allows your sanitizer to work more effectively. A high TDS can cause scaling which can plug heaters. Think of a room filled with colored ping pong balls floating around with each color a chemical. Every time you add something to the water you add more ping pong balls. Eventually balls start colliding with each other trying to move. If chlorine is one color and bacteria is another, chlorine has a much more difficult time getting to the bacteria. While there is no ideal range for TDS the maximum is usually 1,500 ppm over the fill water. High TDS with high calcium hardness and high alkalinity makes water really hard and basic. This can result in scale formations on tile and walls, and can damage heaters. The only way to remedy this situation is to drain the pool, no questions to ask, just drain it.

 

There is a theory that phosphate levels over 200 ppm promote algae growth. Because many fertilizers contain phosphates it is believed it is the source of food for algae. Get rid of phosphates you eliminate the food supply and algae doesn’t live. Phosphates may be in your source water, especially if you live in a rural area and use well water to fill your pool. Another source is runoff from planters or lawns due to heavy rains. Phosphates are be easily controlled by a phosphate remover. Orenda CV-700 is a phosphate remover and an enzyme that helps break down organics while it removes phosphates. A single dose may rid your pool of phosphates for the season. Maintenance dosages throughout the season is a good strategy especially if you have phosphates returning to the pool.

 

To learn more, check out our article: Phosphates & Nitrates: Stopping Algae Growth Before It Starts.

 

While not on the balance list, metals such as iron, copper, silver and manganese can be present in your water as ions. Metal ions are dissolved metals in solution. When these ions combine together they form a solid that falls out of solution and stains surfaces. Metals can be kept in solution by using a metal treatment, chelant or sequestering agent. Overdosing sodium carbonate can promote this ion accumulation. This may result in no metals in solution as they have combined and fallen to the floor.

 

Ideal free chlorine is 3 to 5 ppm, with 2 as the minimum and 10 as the maximum. Chlorine's efficiency can be accentuated or reduced by the many factors listed above. By keeping your stabilizer, TDS and calcium hardness low you allow chlorine to breeze through the room of ping pong balls with ease killing bacteria and oxidizing organics and inorganics.

 

Combined chlorine or chloramines, indicate ammonia in the water. Chloramines cause eye and skin irritation especially with low pH. What you use for a sanitizer may effect pH and alkalinity. Salt water pool chemistry will increase the pH and alkalinity. 

 

pH also has an effect on the killing potential of chlorine. A pH of 7.0 will allow about 80% of your sanitizer to be active with 20% in reserve. While a pH of 8.0 puts your sanitizer at about 20% active with 80% in reserve. Keeping your pH a bit high and adding a few more ppm of sanitizer can yield an acceptable amount of active sanitizer and allow a buffer. This will not cause adverse reactions from your swimmers as the pH and alkalinity are more in line with the body’s natural pH balance. 

 

To reduce chlorine use the chlorine reducing agent sodium thiosulfate. This is not recommended unless you have residuals exceeding 20 ppm as it will eliminate all the the chlorine. 

 

 

Temperature is not a huge factor but it is something to consider for your pool and especially a spa. With a calcium hardness of 200 ppm, alkalinity at 100 ppm, and pH in the 8.0 - 7.1 range, temperatures from 40 degrees all the way up to 140 degrees still maintains the balance within specifications.

 

What does happen in warmer waters is the demand on the sanitizer to kill bacteria and oxidize contaminants increases. The warmer the water, the more swimmers excrete body oils, sweat, dead skin and lotions. This puts a higher demand on your sanitizer the warmer the water. In spas and hot tubs this gets extreme. After just 15 minutes with only two people in the water, the average residential spa will see a complete reduction of sanitizer if there is no means of administering sanitizer continuously. When you consider chlorine starts to gas off from the water at close to 106 degrees you can see why people complain of stinking water with watering eyes and itching skin.

 

Salt water systems have a unique balance issue. When the cell is energized and salt water travels between the plates, sodium chloride (salt) gets split into chloride / chlorine and sodium hydroxide. Sodium hydroxide has a pH of 13 which drives the water balance to have a high pH and alkalinity. Salt water pool owners will have the reoccurring task of keeping pH and alkalinity down. Strategies to reduce the alkalinity to 100 ppm and maintain low levels helps the system to work efficiently. If the balance is allowed to have high alkalinity and pH, the sodium hydroxide forms and falls out of solution onto the pool floor as a white flake or powder. This condition also causes the cell plates to form scale and plug up.

 

Salt water adds to TDS, but it’s a good TDS because it is sodium chloride and not junk. With this in mind, salt water pool owners should deduct the salinity from the total TDS reading to determine what the real TDS actually is. All of the other target chemistry ranges apply, including when to drain the pool.

 

Keeping the salt content at its recommended level is critical for salt systems. Salt reduction comes only as a result of splash out or backwashing the filter.

 

Each of the elements described above hold value in the overall balance of your water. You do not necessarily need to know what they are, all you have to do is get accurate readings from your water and plug them into an index calculator like this one from Orenda.

 

The main items you need to pay attention to are water hardness, TDS, alkalinity, pH and stabilizer. Water harness doesn’t change very quickly so a reading once every several weeks may be good for you. The same goes for TDS. Unless you start dumping a bunch of stuff in your pool, it too is pretty consistent. That leaves stabilizer, alkalinity and pH. I provide the parameter for stabilizer and it will increase with the type of sanitizer you are using so a reading every couple of weeks should show you where you are at. It only really changes when there's splash out, backwashing, or removing water from the pool. That leaves alkalinity and pH. That’s two things to control. Balance alkalinity first and pH will fall into place. Adjust pH with a bit of acid or bicarbonate and your water is great! Those dosages can be determined with a quality test kit like the Taylor K-2005 or LaMotte 7-Meter Test Kit. Something a pool owner who takes care of their pool should have. Salt water pool owners should have test strips to test their water weekly.

 

You should now be ready to go out there and balance your pool water! But if you have any questions, feel free to give us a call. We're open seven days a week and welcome your questions -- (888) 836-6025.