Pool Water Testing Blog

The main reasons people get sick from pool water: Too little sanitizer, improperly balanced water, poorly filtered pool water, and poorly circulated pool water.

While the CDC (Center for Disease Control) cannot do a whole lot about the latter reasons, it does want to help pool owners learn how to properly test for free chlorine residual in their pool water.

On this page on the CDC web site we found the following instructions for practicing free chlorine testing at home:

Testing the strips at home before visiting the pool can help you learn how to properly use and read them.

In order to test at home, you will need:

• 3 containers
• 13 cups of regular tap water
• 3 drops of liquid chlorine bleach *please note that if bleach is more than 3 months old, it may be too old to provide an accurate test

Allow tap to run for about 2 minutes

• Fill container 1 with 1 cup of water
• Fill containers 2 and 3 with 6 cups of water each
• Add 1 drop of liquid chlorine bleach to container 2
• Add 2 drops of liquid chlorine bleach to container 3

Test each container of water utilizing the strips and the manufacturer’s instructions and compare your results to the values below:

• 0 to 1 ppm free chlorine expected
• 2 to 3 ppm free chlorine expected
• 4 to 5 ppm free chlorine expected

Many people assume they know how to use their pool test strips because the instructions seem so simple and easy to follow but in reality a good number of pool owners perform pool water testing incorrectly. also, a good number of pool owners use out-of-date reagents and test strips. A definite no-no if you want to get accurate test results!

Ordinarily the title of this article would mean a dirty individual has decided to take a dip in the water but not this time. Today it means a SMART pool or spa owner dropped a product called a Scumball into the water.

Scumball simply float around on the surface of the water soaking up body oils, tanning lotions, etc. so that less of that stuff becomes a ring around the edge of the pool or spa.

These bad boys can soak up 40 times their own weight before needing to get… rinsed with clean water, cleaned and reused!

So, if you would like to reduce the amount of pool wall scrubbing you have to do this pool season we suggest you consider allowing Scumballs to hang out in the water.

Or, if the idea of swimming with scumballs just plain offends you, take a look at pool additives like Pool Perfect and Pool First Aid that use enzymes to break down oils and greases in pool/spa water.

Each time when you go to the pool store to get chemicals — or floaties for the kids’ arms — one of the men or women at the counter probably suggests that you add some sort of pool water clarifier (sometimes called a pool water polisher) to give it that perfectly clear appearance… but do they ever take the time to explain what the contents of that magical bottle actually DO?

If not, then today’s your lucky day because we will now tell you, in really simple terms, what that mystery stuff does: It makes suspended solids in the pool water stick to one another so that the filter can more easily catch them.

Each brand of pool clarifier has a slightly different method of accomplishing that goal, but in the end they all pretty much do the same thing.

OK, well what is a pool FLOCCULANT, then?

The term flocculant refers to chemical compounds that cause smaller suspended particles to stick together for the purpose of making it easier for a filter to catch them or to cause them to precipitate out of the water and fall to the bottom where a pool vacuum then removes them from the water.

More or less all clarifiers and water polishers qualify as flocculants but, according to recent pool chemical marketing trends, the ones that actually CALL themselves flocculants get recommended for more serious pool water clarity problems.

Any problem with using clarifiers on a regular basis?

With chlorine based sanitizer systems (powders, tablets, liquid, sticks, etc.) we have not heard of any real reason to not use clarifiers on a regular basis. As always, though, we suggest reading and following the directions on the bottle. Not all clarifiers have the same directions for use!

Pressure building in filter after adding clarifiers?

Do not panic! Roughly 9 times out of 10 this means the clarifier has made it easier for your filter to catch dissolved solids previously too small for the filter to catch. Simply backwash the filter each time this happens — or ‘bump’ your DE filter if you have that option — and let your filter get back to doing its job.

Filters that use DE (Diatomaceous Earth) to coat their filter elements will tend to clog and require ‘bumping’ or backwashing more quickly than sand filters due to the efficiency of their filtering mechanisms. In extreme cases the filter elements (fingers, grids, etc.) may need a good cleaning and possibly acid washing soon after you clear up your water problem.

Read the label on the clarifier you select and make sure to heed any warnings regarding the use of that product with certain types of filters.

Can clarifiers take the place of chlorine, bromine, etc.?

Absolutely NOT! Chlorine, bromine and other pool water sanitizer systems serve a completely different purpose and you should not decrease the amount them used because you start adding a clarifier product to your water.

Pool sanitizers help to keep the water in a pool safe from bacteria, germs, etc. Pool clarifiers help get unwanted dissolved solids out of the water.

Each year Gremlins sneak into people’s sheds, garages and pool cabanas with one goal in mind: To steal pool test kit reagents! If you, like thousands of other innocent pool owners, have fallen victim to those evil little bastards, the links below will certainly come in handy:

Don’t own a test kit, yet, or need to replace your whole kit? Check out Pool Center’s Pool Test Kits Page for information on some of this year’s best selling pool water test kits.

Oh, and for those in search of a simple dip-n-read test strip for pool water testing, Water Testing Blog now carries the Pool Check 5-in-1 Test Strip and several other test strips for swimming pools.

We often get asked for advice on how to save money on pool chemicals — especially since gas prices won’t go down and more people have to keep a closer watch on their finances.

Thus far we have found two main ways that pool owners can save money on pool chemicals:

1) Test Your Pool Water: By keeping your water in balance you can avoid costly pool water problems like algae, staining, etc. that all require chemicals to correct. A pool with the correct chemical balance ought never see the likes of algae or staining!

2) Chemical Value Packs: Buying in bulk at the beginning of the season when pool supply companies like In the Swim and Pool Center offer great deals on combination packs of pool chemicals and supplies that you will need over the course of the season will save you time and money in the long-run.

When opening a swimming pool too many people forget to TEST THE WATER before adding chemicals… Whether you choose to test the water yourself w/ test kits like the eXact Micro 7+ Pool Testing Meter or Pool Check Test Strips, or visit your local pool supply store and have them test your water at the beginning of the season, you will want to test for all or as many of these water quality parameters as possible. Note:

• Alkalinity – Not having the correct amount of alkalinity in your water will make getting and keeping the pH of your pool water very difficult.

• Calcium Hardness – Having too much calcium in your water could result in deposits forming and could also make it harder for other chemicals to dissolve in the water. Too little calcium in the water could result in pool water becoming aggressive and starting to attack various pool surfaces.

• Chlorine (Free) – If you use chlorine as your sanitizer, check to see if you have any left over from last year… or risk adding more than you need to add at the beginning of the year and ‘wasting’ money.

• Chlorine (Total) – If you use chlorine as your sanitizer and shocked your pool at the end of the previous season (as you SHOULD have), then you may have a lot of combined chlorine in your water that needs to get ‘burned out’ w/ a non-chlorine shock. Combined chlorine does little good when it comes to keeping pool water clean.

• pH – Incorrect pH levels drastically reduce the effectiveness of important pool chemicals such as bromine, chlorine, clarifiers, algaecides, etc.

• Metals – Having unwanted metals such as copper and iron in your pool water when you shock it w/ an oxidizer like chlorine or bromine at the beginning of the season could cause the metals to precipitate out of solution and stain pool surfaces.

• Stabilizer – Also known as cyanuric acid, having too little of this compound in pool water makes it difficult to maintain a free chlorine residual. Having too much of it can keep chlorine in a pool from doing its job.

• Total Dissolved Solids – Too many total dissolved solids in pool water will result in the water not accepting additional material… such as the chlorine powder (granules), tablets, sticks, or pool chemistry balancing chemicals.

So, get your water tested before adding start-up chemicals. Any questions?

Rather than go into a (boring) chemistry lesson we will address the reason WHY so many of you have asked us this question: You want to know what it is because the pool guys left a bag of suspicious looking white powder at your house and didn’t tell you why.

DE (Diatomaceous Earth) Pool Filters

While many swimming pool filters use just sand as their primary filtration media, a good number of other pool filters use cloth-like filters covered in diatomaceous earth to filter pool water. The DE powder filters out particles far smaller than sand can remove and the cloth-like material over plastic framework stops large particles and debris from getting through.

Proper Use/Addition of Diatomaceous Earth

First and foremost, consult the manual that came with your filter system to make sure you actually HAVE a DE filter. Then, while you have the manual out, read the sections about starting a DE filter, backwashing a DE filter and cleaning a DE filter. Taking a few minutes right then and there to learn the correct way to care for YOUR filter system will save you innumerable headaches — and possibly a huge amount of money — down the road!

Now that you’ve read the manual you know that you should never operate a DE filter without adding the correct amount of DE through the skimmer, you need to replenish DE powder after backwashing and that once or twice a year you may need to put your filter elements (the ‘cloth’ covered things in your filter) through a process called acid washing (i.e. muriatic acid bath) to dislodge embedded microscopic particulates from their cloth covers…. right?!?

And for the record, you may NOT substitute cyanuric acid for muriatic acid, a chemical you will have to get from your local pool store or hardware store. Careful, though, if using product from a hardware store as it may have a much stronger concentration than its counterparts from the pool supply store!

Oh, and before we forget, many pool supply stores offer acid washing services with 48 hour turnaround times… in case you don’t feel like messing around with caustic chemicals in your backyard.

Not everyone has the opportunity or ability to open their swimming pools right when Summer starts to peek around the corner. Travel plans, work, attending school graduation functions, weddings and a host of other events can quickly fill up a family’s free time… and make opening the pool a waste of time — until it gets REALLY hot out and all those other activities come to a screeching halt!

The questions quickly becomes, “Does opening a pool later in the Summer mean adding different pool chemicals?”

In most cases, no, with the exception of chlorine or your primary sanitizer. Warmer water temperatures may have ‘driven off’ winterizing chemicals and allowed the water to turn some shade of nasty. You may find that you need an extra amount of your sanitizing system’s shock treatment to get your water back to a pristine, clean and clear state.

If you normally require pH, alkalinity and calcium hardness balancing chemicals when you open earlier, you will most likely still need them now. Proper use of algaecides and metal removing chemicals goes with out saying… right?!?

Didn’t see what you needed? Take a look at the pool chemicals section of the Pool Center Web Site for additional pool opening and pool maintenance chemicals.

A common mistake made by new and veteran pool owners alike: Assuming their tap or well water contains no dissolved metals. This mistake often results in the formation of ugly, hard to remove metal stains on pool water surfaces once chlorine shock gets added to the water.

What happened?

Simply put, the metals ‘hooked up’ with chlorine molecules to form insoluble precipitates (solids) that dropped out of solution, landed on surfaces and took up permanent residency.

On an unrelated note, we never thought we’d get to use the term ‘hooked up’ to describe a chemical reaction, but alas, we most certainly just did. One point for us!

Getting rid of pool stains?

Definitely NOT a fun task! Often times getting rid of stains will require multiple applications of pool stain removal chemicals and a LOT of elbow grease. Therefore we suggest NOT getting pool stains in the first place and pool owners have several ways to prevent pool stains at their disposal.

Preventing pool stains caused by metals?

Step number one involves testing source water for dissolved metals with a product such as Water Metals Check. One COULD use a more sophisticated method such as a ‘wet kit’ from Taylor, but those kits require a bit more skill and certainly cost more money.

Don’t get us wrong, though. Taylor Test Kits have a definite place in the world of metals testing. If the Water Metals Check test strips indicate the presence of dissolved metals, some of the Taylor Test Kits will help determine which metal your source water contains.

Step number two involves adding a ‘sequestering compound‘ to your pool water BEFORE adding the initial dose of chlorine shock. The sequestering agent will, in the proper dosage, bind with all dissolved metals in the water and render them incapable of forming precipitates (insoluble solids) with chlorine molecules.

Oh no! I’ve already got stains! Now what?

You, my friend, FIRST need to figure out what insidious metal has invaded your precious pool water using a kit such as the Jack’s Magic Pool Stain ID Kit. Otherwise you may find yourself doing a whole lot more scrubbing than needed and buying far more Pool Stain Treatment Products than needed.

Once you’ve pinpointed the offending metal, select the correct treatment option. Jack’s Magic, an industry leader in the field of preventing and eliminating pool stains makes specialized products designed to remove stains in pools caused by pretty much any metal commonly found in water used to fill swimming pools.

And after the stains are gone?

After you’ve wiped out ugly pool stain caused by the intrusion of dissolved metals, you have NOT finished the job! Now you must figure out how metals got in your pool and eliminate those sources. Next, we suggest the use of something like Jack’s Magic Blue Stuff to help prevent future staining.

A common question we have heard many during our tenure working in pool stores over the years: “How does a pool clarifier work exactly?”

Despite our knowing a bit more than the average person about chemistry and wanting to share that knowledge, we usually refrained from going into a lecture about polymers and such… for fear for of scaring the poor customer half to death and causing them to have horrible nightmares that night about their experiences in high school chemistry class.

Instead we told people to imagine that the bottle of pool water clarifier in their hand contained millions of little greedy squid and octopuses that had a craving for small particles in pool water. Simply pour the little buggers into the pool and in a short period of time each of them would fill up their arms (tentacles) with as many particles as possible until full and get so big that the pool filter would catch them or they would fall to the pool floor waiting to get vacuumed out.

Sounds silly, and almost stupid, but we sold a LOT of pool clarifier using that little story. Something about the imagery of small animals doing all the work for people seemed appealing… but that’s just our best guess.

Moral of the story?

Adding live sea creatures to pool water will have BAD consequences… but adding some sort of pool water clarifier to your pool water will put advanced chemistry (in the form of greedy squid and octopuses) to work for you, help clear up cloudy pool water, and/or help keep clear pool water sparkling clear.