Pool and Hot Tub Water Maintenance

Water Talk
http://www.greatesc.com

Water Chemistry made simple, or at least as simple as possible

Pool and Spa Chemistry and Water Balance. Pools and spas are great, but they can become your worst nightmare if the water chemistry isn't up to snuff. Browse around for the information you need and if you have any questions please feel free to go to http://www.greatesc.com/sunbreeze/index.html (Our Spa Service Company) and we will try to help.

Pool and Spa Facts. This is a new section and we hope it will help answer your questions and help others. We take your E Mails or queries in the search engines and try to answer the question in this Faq area.

This is the most important area of spa maintenance. It can happen in a day or not for a year, but when it happens, it can get ugly. Change your spa water often. If your water appears milky, or you cough while in the water, change it.

TDS

Let's tackle the why question first: The most common reason for draining a spa is because the amount of total dissolved solids in the water has reached its maximum allowable level. As a general guideline, spas should be drained when the TDS level reaches 2,000 to 3,000 parts per million or 1,500 ppm above the start-up TDS level.
By definition, TDS is absolutely everything dissolved in the water - from metals to chlorine to bromine, alkalinity, salts, bather waste and more. And when the amount of these substances in the water gets too high, it can cause a number of problems, including salty-tasting water, colored but clear water, algae growth, metal corrosion, cloudy water, eye and skin irritation, false test readings, coughing, and black mold.

What causes TDS levels to increase? When water is heated, aerated and agitated - as is the case with water in spas - the water's evaporation rate increases significantly. This, in turn, dramatically affects the TDS levels in spa water because only the water evaporates; anything else that may have been dissolved in the water gets left behind.
As the water level in a spa drops, the first prescribed action is to add make-up water. But while this water will have a relatively low TDS level, it too will evaporate eventually, adding its share of TDS to the remaining water in the spa. As this cycle continues, the spa water's TDS levels will continue to climb.
TDS levels are also increased whenever the spa water is treated chemically. For example, adding as little as 1 pound of dichlor, trichlor or bromine tablets to 500 gallons of water can create an increase of 240 ppm to the water's TDS level.
And it does not take long for that much dichlor to be added to the spa: In addition to the 1 to 2 ounces of dichlor needed for regular chlorination each week, many owners use their spas two or three times a week, each time adding another ounce of dichlor. At this rate, it would only take three weeks or so to raise the TDS levels by 240 ppm.
Many other common spa products also contribute to a spa's TDS count, including algaecides, algae preventers, acid, sodium bicarbonate, clarifiers, scale inhibitors, foam suppressants, stain inhibitors and nonchlorine shocks.
For example, if a spa owner adds a 2 ounce dose of a nonchlorine shock to the water after each use, that dose alone will produce about 28 ppm of TDS in a 500-gallon spa.
Another contributing factor here is bather waste. just 3 pints of human sweat can produce approximately 4 grams of salt, which would add approximately 2 ppm to the TDS of a 500-gallon spa. In the case of a commercial spa that may handle an average of 25 bathers a day, the amount of TDS from human sweat alone could be as much as 50 ppm every day.
And don't forget, bathers also bring with them residual soap, deodorant, hair spray, suntan lotion, body oil, hair gel, laundry detergent, hand lotion, cosmetics and other personal-care substances - all of which can contribute to the build up of TDS.
When you consider the possible factors that could contribute to the spa water's TDS, it's easy to see how the TDS level can climb very quickly and why frequent draining is needed.
Now, as to how often a spa should be drained, the National Spa & Pool Institute suggests the following formula: One-third of the spa's gallonage divided by the average daily bather load equals the number of days that the water can be used.

(Gallons x .33) -- bather load = days of use

For example, a 1,200-gallon commercial spa with an average bather load of 25 people a day should be drained after 16 days of use:

(1,200 gallons x.33) - 25 people = 16 days of use

For residential spas, however, most experts would agree that draining a residential spa every three months is Necessary.

Signs that may tell you that your spa has TDS. One sign is that you are constantly reading low alkalinity and adding A+ every week. Another good sign is a milky look to the water, especially when you turn the air on to your spa. I have found also that a sudden and incurable development of black mold on the cover , behind the pillows, and around the controls. And one final sign, and this is after it has gone to far is that you find yourself coughing when you are in the spa. If you are experiencing any of this change the water, it's better to change your water too often than not enough.

Pool & Spa water pH

The pH is one of the most important factors in pool water balance and it should be tested and corrected at least every week. pH is the measure of how acid/ alkaline the swimming pool water is. A pH of 7.0 is neutral - below 7.0 is acidic, above 7.0 is alkaline. The pH of our eyes is 7.2 . No wonder that the ideal pH for your pool is just that - 7.2 , and should be kept within the range of 7.0-7.6 .

What happens when the pool is too acidic?
(pH is low)
If your swimming pool is Marbelite or plaster, the pool water will begin to dissolve the surface, creating a roughness which is ideal for pool algae growth. A similar result occurs in the grouting of tiled swimming pools.

Metals corrode - and this includes swimming pool equipment, pipe fittings, pump connections, etc.

As the swimming pool walls and metal parts corrode, sulphates are formed. These sulphates are released from the water onto the walls and floor of the swimming pool causing ugly brown and black stains.

Chlorine, which is used as a disinfectant in the swimming pool water, is activated and lost to the atmosphere very quickly. The water is not being sanitized, and we are throwing away our money by adding chlorine when the pH is too low.

When we swim, our eyes and nose burn. Our swimwear fades and perishes. Our skin gets dry and itchy.

What happens when the pool is too alkaline?
(pH is high)
The calcium in the swimming pool water combines with carbonates and forms scale, just like in our kettles. This calcification is seen most at the waterline, where it traps dust and dirt, turning black with time.

The swimming pool water starts to become cloudy or murky and it loses its sparkle.

The calcium carbonate has a tendency to plate out on the sand in the swimming pool filter, effectively turning it into cement. So your sand filter becomes a cement filter, and loses its ability to trap dirt from the pool water.

As the pH rises, the power of the chlorine to act on foreign particles is lost. At a pH of 8.0 the pool can only use 20% of the chlorine you put in. So 80% of it goes to waste and you would need 5 times as much chlorine to provide the disinfection you need.

In alkaline swimming pool water, the swimmers suffer too. Our eyes and nose burn and our skin gets dry and itchy.

By neglecting to test and correct the pH of swimming pool water, we not only cause it to become unsightly, but we also cause ourselves physical discomfort. In addition to this, we insist on throwing away our hard-earned money on swimming pool chemicals that cannot possibly be effective in that pool water.

After testing the water, the necessary chemicals must be added to bring the pH to a level of about 7.6

Testing the chlorine

We recommend the Taylor Complete High test kit Part # K2005

When planning to buy a test kit to measure the chlorine levels in your pool, it is important to remember that there a 3 aspects which can be measured:

Free available chlorine (or residual chlorine) - is the amount of chlorine in the pool that can sanitize or disinfect the water and is the important measurement for us.

Combined chlorine - consists of undesirable, bad-smelling, irritating compounds which form when there isn't enough free available chlorine.

Total chlorine - is the total amount of chlorine in the water. It includes both free available and combined chlorine.

We are interested in how much available chlorine there is in the water - chlorine that can act on foreign substances in the water to keep the pool clean and safe for the swimmers.

Too little chlorine results in algal and bacterial growth, waterborne illnesses, cloudy water and insufficient sanitation of the water.

Too much chlorine can result in eye, nose and skin irritations. Remember, too, that the chlorine in the pool is carcinogenic and we should aim to keep its level to the minimum required for complete disinfection.

Test kits which use tablets rather than liquid reagents are preferred. The tablets are easier to use and provide more accurate results. Also make sure that the chlorine measuring tablets are "DPD" as only these can measure the free available chlorine.

Take the water sample from at least 20-30 cm below the surface and at least that far from the wall of the pool. Test the water according to the test k