Beginner's Guide to Pool Chemistry & the BBB Method

. . . . from the original (2006) version of this page:

Quote Originally Posted by Watermom View Post
I copied this from a post made by a fellow moderator - CarlD. Very good information in a nutshell of the basics behind what pool chemicals are needed in a pool and why. It was originally written as a reply to someone about to install an above ground pool, so some of the info is aimed at caring for a vinyl pool. However, most of the info is relevant for all types of pools. Great post, Carl!

OK, the BEST and fastest way to get up to speed is to go to the sister site, PoolSolutions.com and start reading. Click on "Site Map" and go to the section marked "Info From Pool Solutions" and read everything there. No joke. It's very interesting and informative and will give you a wonderful foundation.
This version (July 2018) updates both the page, and the BBB Method it described . . . which implied more emphasis on baking soda than it should have, and not enough on stabilizer.

For those of you new to the PoolForum, I -- PoolDoc / Ben -- created the "BBB Method", though not that name, which was invented by CarlD. Unfortunately, the name put more emphasis on specific chemicals than I ever did. Bleach IS a useful source of chlorine, because it is always available AND has no OTHER side effects. Borax is a useful pH increaser for the same reasons. But baking soda was only on the list because it was an example of a "pool chemical" you could buy at the grocery store, not because it's needed much!

But over time, the name, "BBB Method" got away from us, and came to mean things that weren't always helpful. This page updates the *original* "BBB Method" and corrects some old misunderstandings. It also adds a couple of things I've learned, since 2006!



All the chemicals and shorthand gets confusing, but the idea is to keep your pool sanitary by killing all the algae & germs in it, and clear by keeping the pH right and the chlorine high enough to 'burn up' stuff the filter can't remove.

It all seems SO confusing but it's not. We'll say this a lot, but there are two things that matter: chlorine to sanitize your water, and pH to ensure it's neutral and not too acidic and not too basic.

These TWO things -- chlorine (FC) and pH (pH) -- are the keys to pool care.

But there are two other factors that make this possible: stabilizer and alkalinity.

Alkalinity (TA) is easy: baking soda adds it; low pH + aeration (bubbles) remove it. What it does is also easy: it makes the pH 'sticky'. Without enough alkalinity, pH can bounce up and down. Fortunately, most water ALREADY has enough alkalinity for vinyl and fiberglass pools, and you only have to worry about it, if it's too high. Unless you have a concrete pool, TA between 60 and 150 ppm will usually be fine.

Stabilizer (CYA) is a little more complicated. It prevents sunlight from quickly destroying the chlorine in your pool. But it also slows down chlorine's activity. So, if you don't have ENOUGH stabilizer, your chlorine will disappear in just an hour or two of full sun. But if you have TOO MUCH, your chlorine will barely be active. Generally, levels between 30 and 90 ppm will be OK . . .

BUT . . . the correct chlorine level is determined by your CYA level! This is really, really important, because if you DO NOT know your CYA level, you CAN NOT KNOW what your chlorine should be.

So, what should your normal chlorine level be? 2 ppm OR 5% of your CYA, whichever is higher. If your CYA is 40, you need to maintain 2 ppm. But if your CYA is 80, you need 4 ppm!


OK, some explanations:

You've heard about the pH scale, which runs from 0 to 14, in basic science class. Super-acid, like pure hydrochloric acid is "0". Super-basic (or alkalkine), like pure lye, is "14". Lemon juice & vinegar are weak acids; baking soda & borax are a weak base. Your body's pH ranges, from lemon juice to borax, so to speak. But for several reasons, your pool, needs to be just above neutral, or slightly basic, & usually should range from 7.2 - 7.8

We lower pH if it is too high with acid -- 31% muriatic acid (Hydrochloric Acid) or dry acid (granules). You can get Muriatic Acid at most hardware stores.

We raise pH if it's too low with ordinary 20 Mule Team Borax which you can find in a green box in the laundry aisle at Walmart. You can use Soda Ash as well (sodium carbonate -- called Washing Soda) but it will raise both PH AND carbonate alkalinity. If you only want to raise the PH, use Borax.


Chlorine is our sanitizer. It kills algae & germs and is the ONLY sanitizer you should use for fecal matter. It also gets rid of excess suntan lotion, and other stuff. The least complicated way to add chlorine in small pools is with plain LAUNDRY BLEACH, or with more cncentrated pool bleach. Walmart has both.

Other forms of chlorine are useful . . . but have side effects. For example, dichlor is 55% chlorine and 50% stabilizer (I know, the %'s don't add up. See note #1). If you NEED stabilizer, that's good. But if your stabilizer is too high, that's bad.

We measure chlorine with test kits. You must be able to test pH, chlorine, and stabilizer. There are other things you can test: total alkalinity (TA), calcium hardness (CH), acid demand (AD), base demand (BD), salt levels, phosphates (PO4), etc. But those are less critical. Test strips are moderately accurate for pH and chlorine, but not accurate at all for stabilizer, and since you MUST know your stabilizer level, you need a different kind of kit.

The cheapest one that will do what you need is the HTH 6-Way Test Kit (made by Taylor) from Amazon or Walmart . . . to start. Eventually, you'll need the Taylor K2006. And if you want to 'get it all' now, you'll also need refills for the CYA test: 16 oz bottle of R-0013 and Disposable plastic lab funnels


Chlorine: Free, Combined, Total

There's been a lot of discussion, in pool circles, about free chlorine (FC) vs combined (CC) or total chlorine (TC). If you have an outdoor pool, and follow our instructions, that distinction won't matter: the chlorine in your pool will BE "FC" or free chlorine. Chlorine levels should be between 1 and 50 ppm, but you should start with 3 ppm, and then adjust based on your CYA and whether the pool is operating well.

Chlorine Fear: Rational or Phobic?

People get scared of chlorine in pools. They shouldn't. We've had long, complicated, and confusing discussions here on the topic. But the bottom line is: the danger from chlorine is GREATLY exaggerated, especially on OUTDOOR pools. Here's a quick reality check. Dermatologists and pediatricians have been using "bleach baths" to treat ecsema and other skin conditions for YEARS, no prescription needed. Bleach baths involve soaking in 50 - 100 ppm, with no stabilizer. They do this with SMALL children! (By the way, those levels of chlorine WON'T damage bare skin, but WILL damage swimwear, especially expensive fashion swimwear.)


Other stuff

CYA is stabilizer. You need this to keep sunlight from breaking down your chlorine too fast and leaving you with none. The best way to add stabilizer is to use dichlor to chlorinate . . . for awhile. It's about 50% chlorine and 50% stabilizer. You can get it at Amazon (#1, #2, #3) or Sams Club. Aim for 30-50ppm, unless you have a salt system, then aim for 80 ppm. Add less than you think you need because the ONLY good way to lower it is dilute it by draining off water.

"Total Alkalinity" (TA or Alk) is confusing, because it doesn't mean how basic (high pH) the water is, but how much your pool water will resist change in pH. For simple pools, you just need 'some'. Baking soda increases it, but don't worry about it, unless your pH is jumping around.

Calcium Hardness (CH) is virtually irrelevant for a vinyl pool. But pool store guys will swear on their mother's life that you need it. Unless you have a concrete pool or a pool heater, it's simply not true. Calcium in the water prevents the water from sucking calcium out of concrete or poolfinishes like plaster or Diamond Brite. It is just not an issue in vinyl pools. It only matters to you if gets EXTREMELY high--500ppm.


Only what you need
One of the MOST important ideas in the original BBB concept is this:

Add what you need . . . and NOTHING more!

Never, every add a pool chemical because 'it might help'. Trust us; it probably won't and will often make things worse.

Here is a really, REALLY important idea to understand: pool stores and pool chemical companies make LITTLE money when your pool runs smoothly and LOTS of money when it's all messed up.

Let's put that another way: if all pool owners followed the BBB Method, more than half of pool stores would go out of business!


Basic 'BBB Method' Chemistry:

That's about it: Chlorine, pH, & CYA are what you need to maintain:
  • pH between 7.2 and 7.8
  • CYA between 30 and 60 ppm (80 with a salt system)
  • Chlorine at least 2 ppm but otherwise 5% of CYA

We often use Bleach to chlorinate and sanitize, Borax to RAISE pH, muriatic acid to LOWER pH, and stabilizer, either directly or via dichlor to make chlorine last. (Baking soda, the other 'B', is only rarely needed.)

Once you get the hang of it, you'll need to test 2x and add chemicals 2 - 4x per week. If you are using bleach, and an OTO kit (like the HTH 6-way), doing ALL this may take only 20 minutes per week.

Occasionally, you'll need to test more elaborately with the K2006. That takes longer, but the more experienced you become, the less you'll need it!


To be continued . . .