"What chemicals are in my swimming pool?"
I got emailed this question the other day and decided to write a quick post about it. I'm going to try and answer this question as best as I can, and I think in order to do that I might need to rephrase it a bit. I think what this person is really asking, and a question that is a bit more realistic is, "What chemicals do you put into the water to maintain my swimming pool?" The thing is, water is strange and very old, and over time a ton of stuff can get dissolved inside of it. Most of the material found in water we would never test for or worry about while maintaining a swimming pool on a regular basis. So I cant actually know for sure every possible thing that could be dissolved inside of your pools water without getting super scientific with things like spectrographs, incubators and probably hours and hours looking through a microscope. What I do know for sure, and what I can answer is what chemicals are added to a swimming pool on a regular basis in order to keep the water clear throughout the year.
So below I've created a quick list of all the chemicals that we could possibly add, with descriptions of there purpose included.
1) Chlorine - This one is obvious. We use chlorine in order to kill any organic matter that ends up in the water. So, if your swimming behind someone with the flu virus and that virus swishes out of their mouth and gets sucked into yours. The chlorine makes sure that flue virus is dead the moment it hits the water. Makes you rethink public swimming pools huh?
2) Muriatic Acid - This acid is technically just a less pure form of the acid found in your stomach (hydrochloric acid). The main reasons we add acid to a swimming pool is because we are constantly trying to regulate its PH (Potential Hydrogen). Keeping the PH in a certain range ensures a couple of different things such as, your eyes not burning when your jump in. Your eyes have a PH of 7.0 to 7.3 and 7.2 is considered the sweet spot for swimming pool water. Another reason is that water too acidic (PH < 6.8) or too base (PH > 7.8) can have adverse side effects on the pool. Such as causing equipment to wear out faster or causing etching in the plaster. The last reason, and probably the most important, is for the chlorine itself. The effectiveness of the chlorine depends on the PH level. Too low a PH will cause the chlorine to dissipate quicker and too high a PH will cause the chlorine to be less effective at killing that flu virus we mentioned earlier.
3) Calcium - This one is strange, for some reason water needs to have a certain amount of calcium in it to be balanced or else it will leach the calcium from wherever it can. Normally it will get it from the pool plaster and that can cause some very bad side effects.
4) Cyanuric Acid - This is another acid, used mainly in conjunction with chlorine. Since free chlorine's natural chemical state is a gas, we have to mix it with some something to keep it in solid form, such as tabs or granular. One of the chemicals that keep it solid is cyanuric Acid, another could be calcium. cyanuric Acid also works to keep Chlorine from dissipating as quickly, making it last longer in the swimming pool. Think of cyanuric acid as sun screen for your pool water!
5) Sodium Bicarbonate - Sodium Bicarbonate or baking soda, is added to a swimming pool when the water is too acidic (PH < 6.8) Since sodium Bicarbonate is a base it will make your PH go up. Fun fact: Sodium Bicarbonate is also used to make bread fluffy when you cook. It does this by producing carbon dioxide when mixed with an acid causing bubbles that make the bread rise. Kinda like blowing bubbles in your milk and then freezing the milk!
6) Lanthanum Carbonate - We actually call lanthanum carbonate Phos free and its used to remove Phosphates from your swimming pool. What are Phosphates? A phosphate is a salt containing phosphorus which is an element on the periodic table. Phosphorus is essential for all living things to grow including humans, but specifically what we are worried about in regards to a swimming pool is algae. Phosphates and nitrates act as fertilizer for algae and the only way to get them out is to add lanthanum carbonate to the water. The lanthanum will coat your filter causing it to catch the phosphates which normally pass right though.
7) Copper, Iron and other metals - Metals are found in pool water and which ones are found vary from pool to pool. Copper is found in some algaecides and could also be found in your plumbing depending on your house. If you live on a well system, all sorts of metals and minerals could be in your water such as magnesium and iron. We really don't add metals (except copper if you have some really tough algae), but more than likely some type of metal is in your pool water. We don't really worry about it unless we start to see discoloration of the water or your plaster around the pool.
Now you know! That's pretty much everything we would add to your pools water to make sure its stays blue. If you have any questions feel free to email in and ask. Bye!