Basic Pool Chemistry

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Basic Pool Chemistry 101

There are 2 basic elements to pool chemistry: water balance and sanitation.

Water Balance

Your pool water is delicate, and in order to reach perfect pool harmony, it must be balanced. Balancing your pool means keeping the pH of the water between 7.2 and 7.6, which is slightly above neutral on the pH scale. There are 3 main ingredients to keeping this balanced: pH, Alkalinity and Calcium Hardness. Proper pH Level: 7.2 to 7.6 pH alone is unstable. Rainwater, swimmers, and just about anything that enters the water can affect the pH level. When pH is low, it means your water is acidic, and when it’s high, you water is basic. pH has a major influence on the effectiveness of your sanitizer, if your pH is low your sanitizer (especially chlorine) will become hyperactive and will be used up quickly. When your pH is high sanitizers lose effectiveness and while you may find your chlorine lasts longer it won’t be half as effective at cleaning your water. Proper Alkalinity Level: 125 to 150 ppm Alkalinity is a pH buffer, meaning it helps to keep the pH from drastically moving up and down the pH scale by absorbing major changes to the waters before affecting the pH. Think of Alkalinity like a bodyguar for pH, if anything wants to change your pH it has to go through Alkalinity first. If your Alkalinity is to low your pH will be left unprotected and can be pushed around as a result. Proper Calcium Hardness Level: 200 to 325 pppm. Without calcium, your water will become hungry for it and seek to fulfill it’s appetite by feasting on your pool’s plaster (if you have a cement pool), the equipment and anywhere else it can get it. Adding calcium to your water will help protect your pool walls and equipment in the long run. However, too much calcium can cause scaling and degradeing equipment.

How To Keep Your Water Balanced

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It’s important to keep your eye on your pH and alkalinity levels – at least once a week – by using a home test kit or test strips.  To keep your pool balanced, you need to keep these chemicals on hand: pH IncreaserPh uppH Decreaser low & SloAlkalinity Increaser Balance Pak 100 If your pH and alkalinity are both high, pH decreaser will lower both. There is no chemical to lower just alkalinity. If your pool is properly balanced at all times, it will make your pool’s sanitizer work more effectively.


The most common form of pool sanitizer is chlorine, but there are others you can use, including: Bromine: chlorine’s halogen cousin Biguanide: Baquacil or SoftSwim Minerals: Silver and Copper   Proper Chlorine Level: 1 to 3 ppm Chlorine is an extremely effective bacteria and algae killer, and cost effective. There are a few ways you can introduce chlorine into the pool water, including: Chlorine tablets Chlorine granular or powdered chlorine Salt Chlorine Generator: turns regular table salt into chlorine Chlorine tablets are the most popular form. They come in 3” and 1” tablets and can be added to a floating chlorine dispenser, a chlorinator, or the skimmer basket(s) in your pool. [NOTE: When buying chlorine make sure you look for Trichlor or Dichlor as an active ingredient. These types of chlorine products are stabilized. UV rays from the sun eat up chlorine, but if it’s stabilized, it drastically slows down this process. Proper Bromine Level: 3 to 5 ppm Bromine is chlorine’s halogen cousin and it more commonly used in hot tubs and indoor pools because it doesn’t give off that “chlorine” smell. Bromine works a little differently than chlorine and it’s not as effective when dealing with certain types of algae. It’s not recommended for outdoor pools in direct sunlight. Sunlight eats up bromine very fast because it’s unstabilized. Silver and copper minerals are introduced to the water by an ionizer that resembles a chlorinator. These minerals work to sanitize the water, but they are much slower than chlorine. A mineral system is NOT a complete chlorine alternative as chlorine is still required – but only a small amount as backup. Proper Chlorine Level: 0.5 ppm Shocking your pool is another term for oxidation. When a chlorine particle attacks and kills bacteria, or other organic material in your water, it forms a chloramine, which is chlorine that doesn’t kill anymore. This particle just floats around in your water until it can be oxidized and broken apart. In order to oxidize these chloramines, you must “shock” the water by adding enough chlorine – or non-chlorine shock to reach breakpoint oxidation. What is Breakpoint Oxidation? To reach breakpoint oxidation, the chlorine reading must be 10 ppm over your combined chlorine reading. Your chlorine has two readings: free chlorine (FC) and total chlorine (TC). Free chlorine refers to the chlorine that is free and available to kill. Total chlorine is those chloramines we talked about. (NOTE: Pool shock products are made with unstabilized chlorine or no chlorine at all. They will go in, do their job, and get eaten up by the sun’s UV rays very fast. That’s why it’s important to shock your pool at night or dusk, and let it work for 8 hours (with the pool running) throughout the night.) You should shock or oxidize your pool at least once a week. Other Types of Pool Chemicals You Need To Know About If you only used pH, alkalinity, calcium, and a sanitizer, you could keep a clean and healthy pool all year long. However, there are a few more products you should be familiar with in case you need or decide to use them Cyanuric Acid (Chlorine Stabilizer) Most chlorine products you add to the water will be stabilized chlorine. However, if you start with fresh water, you might want to add some cyanuric acid as a stabilizer so that the chlorine doesn’t get burned off by the sun’s UV rays so quickly. This chemical will protect your chlorine from the sun. Algaecide Algaecide is a algae preventative. Use algaecide as a backup. If your chlorine levels dip down, and you don’t catch it in time, the algaecide will keep the algae at bay until you can get the chlorine back up. Clarifier and Floc A water clarifier helps by bringing all those tiny particles that are making your water cloudy and combining them into bigger particles that your filter will have a better chance of filtering out. Floc or Flocculant, grabs those tiny particles, brings them together, and sinks them to the bottom. With floc, you will have to manually get those particles out of your water by vacuuming to waste.


Circulation of the pool water allows you to filter your water, which is cleaning. It also helps to spread the chemicals you add to the water, like stirring a cup of coffee after adding cream and sugar. What Makes Good Pool Circulation? Every pool should be equipped with a pump and a filter, at the very least. Circulating the pool water is performed by your pump. The pump sucks in the water from the pool by the skimmer, or the rectangle hole in your pool with the failing door (sometimes). Once the water is sucked out the pool by the pump, it passes through the pump and into your filter. The filter’s job is the clean the water by filtering out particles that are making your water dirty. After it passes through the filter, it’s pushed back into your pool through a jet, which is a little round hole in your pool (some pools have multiple jets and multiple skimmers). Your return jet should be multi-directional, if it’s not I would suggest getting a new jet fitting that will allow you to direction which water the water is pushed back into your pool. This whole process is circulation of the pool water How To Improve Pool’s Circulation It’s good practice to point your return jet in a direction that will spin the water in your pool, hence, circulate. If your pool only has one jet, it’s a good idea to point the jet to the opposite side of your skimmer and downwards. This will circulate the water and also mix the water on the bottom of your pool to the surface. Dead Areas Dead areas are spots in your pool that have poor circulation. Some commons spots include: Behind your ladder(s) In and around pool steps All cracks, creases, crevasses Underneath the skimmer(s). Sometimes these dead areas are unavoidable. You can do your best to point your return jets to improve these areas, but you may just have to take care of these areas manually. This is why it’s important to always have a pool brush handy. Brushing This is a major part of pool circulation. Every pool is going to have a few dead spots, so practicing good circulation also includes brushing your pool. You should brush your pool often, at least once a week. Brushing dead areas and other areas of your pool helps to break up debris or micro-organisms, like algae. It gets these inhabits into the water, instead of clinging to other parts of your pool, so that your filter will have an opportunity to filter them out. Run your pump and filter 24 hours a day if possible. Keep skimmer and pump basket(s) clear of debris. Angle your return jet(s) to spin the pool water in a circular motion. Point at least one jet towards the bottom of the pool. Brush your pool at least once a week and hit all the dead areas.

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