pH

One of the most commonly known chemical aspects of pools, not to mention most important, is pH. pH is just a measurement of the acidity of the water. It is measured on a scale of 0-14. Anything 6.9 and below is considered "acidic", anything above 7.1 is considered "basic", and 7 itself is considered "neutral". When it comes to the water in our pool, we want the pH just barely on the basic side of the scale. Generally, on the number scale anywhere between 7.2-7.6 is fine. So now that we need to know where to have our water, we just need to know the techniques to adjust our pH. Logically, if our pH is basic we would put some acidic chemical in the water to pull that number down into the ideal range, and the opposite applies to it being low, you have to insert a basic chemical. Easy right? But then how much of each chemical to add, and which chemical? Well thats where your local pool store comes in handy. Most pool stores carry water testing equipment, and some will even test your water for free. This equipment will help determine esactly how much to add of each chemical.

Alkalinity

Another important area of water balance is alkalinity. Alkalinity is a little bit harder to understand. The word "alkalininty" it truly defined as the measure of alkali metals in your pool. The practical application of alkalinity is that it works like a buffer it pH. In other words, it keeps pH levels from shooting up or down when a volume of water is introduced to your pool. Adjusting the alkalinity is similar to adjusting the pH, for they are very much related to each other. However, when it comes to adjusting these two levels you will always want to adjust the alkalinity first. Adjusting the alkalinity will have a large impact on the pH if it is very high or very low, however you can adjust the pH without having a large effect on the alkalinity.

Calcium Hardness

The amount of minerals in your water is determined by the "Calcium Hardness". There are many problems that can develop from your calcium hardness level. The most common mineral found in the hardness level is calcium carbonate. Its stability as a molecule, tendency to cling to itself and create "scale" makes it a hassle to control. Calcium hardness is a tricky level to maintain because you cannot easily adjust it down, especially if the water out of you tap has a high calcium hardness. On the other hand, though less common, if the hardness level is too low then the water can become corrosive. As with each sanitizing system, the ranges for calcium hardness varies, but in general you will want your calcium hardness level to be between 200-350. As I stated earlier, calcium hardness is a difficult level to lower, so here are some tips to avoid having to go through the trouble of lowering it: stay away from calcium based shocks, be careful whenever adjusting the calcium hardness level up, and if the water from your tap is already very high don't worry there are methods to lower your calcium hardess. The most common way to lower the calcium hardness is to fill the pool with a water of a lower hardness. There are less common ways like using Trisodium Phosphate or a scale inhibitor of some type, but using water with a lower calcium hardness level is probably going to be be your best bet. As for those of you who cannot lower your calcium hardness level through using our tap water, try consulting a water softening company or if the water in your house is soft (often water softening units do not entail garden spigots that are outside) run it to the pool. You have probably heard that it is not safe to add softened water to the pool, however that is not true for the most part. It is not safe to USE softened water to fill the pool, but adding some softened water to "top it off" is ok. It is difficult to provide a correct amount of water to top it off with because its almost impossible to predict the hardness of your tap water. However, if you use good judgment, or ask you local pool store it should be considerably easier than guessing blindly.

Total Dissolved Solids

Let me say first and foremost that "pool professionals" pay way too much attention to this chemical level. They blindly blame many problems on TDS because they do not truly know what the problem is. Let's first take a look at what TDS is so you can fully understand it. TDS, simply put, are minerals and other chemicals that are smaller than two microns. They are are classified as "dissolved solids" because they are broken down as completely as they will ever be in water, but they still have enough substance to them to be considered a solid. The total dissolved solids, or TDS level, is how many parts per million (ppm) of these solids are in your water. Mostly comprised of calcium and sodium compounds, this rising issue comes from using salt systems, or chlorine tablets instead of using straight chlorine gas. However, if your local pool care professional is pushing you to drain your pool because of this level, it probably is completely unnecessary. The average pool care professional is trained to tell you to drain your pool at a TDS level as low as 1500 ppm. It is rarely necessary to drain your pool even at 4000ppm or more. I say rarely because about 5% of the time it could be, but draining your pool should be a last resort! Now, you probably want to know the basis of this argument. Look at the sea. The ocean has a TDS level close to 30,000ppm, and in some areas of the ocean you can see as deep as the light shines. Bottom line, don't drain your pool unless you need to, and usually there isn't a good reason to, even when it comes to TDS.