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Four Things to do When you Open a Pool with Crystals in it

What are you going to do if you remove a winter pool cover and find calcium crystals in the pool? If you have encountered the winter crystals in the past–and you may have thought it was ‘scale’–what did you do in the past? Did it work? This article will outline four things Orenda recommends if you are trying to open a pool with crystals in it.

1. Prepare for the worst, Hope for the best

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Having Sodium Bicarb and Calcium on your service truck helps balance the LSI.

If you winterized your pools, be on the safe side, and prepare your service vehicles for spring openings. Assume you will encounter at least one pool with crystals. What will you need to rectify the problem? Calcium chloride, sodium bicarbonate, and SC-1000Be sure to have some empty buckets on every truck, so you can pre-dissolve calcium and/or bicarb prior to adding it to the pool.

Prepare for the crystals by having bags of calcium and sodium bicarbonate on your truck. You may also need our SC-1000, which is a non-acid-based chelant to dissolve the calcium back into solution. Don’t be fooled by high water chemistry that drifted up in the winter to find LSI equilibrium. Those high chemistry readings happened at the expense of your surface.

If you have liner pools, do not expect to find a liner pool with crystals in it. The calcium crystals have to come from somewhere…and if your water is deprived of calcium, a liner will not provide that calcium. That said, rectifying the LSI is still your number one priority when opening the pool.

2. Test water chemistry thoroughly, and collect crystals as samples

You will need a test kit AND a thermometer. Test for everything you can: water temperature, pH, total alkalinity, calcium hardness, cyanuric acid and TDS/salt. Plug those results into the Orenda App. Using the app, find out what it will take to balance the LSI of the pool.

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This water was tested by a customer during opening day 2017. The pool was covered in calcium crystals, yet the pH was well above 8. It is evidence that water ‘drifts up’ when it is aggressive, because it is finding equilibrium on its own. Colder water needs higher pH to stabilize the LSI.

If you do encounter a pool with crystals, chances are, the chemistry will be surprisingly high. It’s the opposite of what we would expect, right? In fact, in most cases we have seen, these pools have a pH above 8.0, and a calcium hardness level significantly higher than what the pool was closed with. Why? Because the water sought LSI equilibrium on its own…at the expense of your surface. “Drift up” anyone?

Using our Orenda LSI Calculator App, you can see the impact that water temperature plays. It is our belief at Orenda that water temperature is the main driving factor for aggressive water in the winter. If you did not prepare for the cold water when you winterized, chances are, your water found equilibrium on its own…or at least tried.

Collect samples of your crystals

This is important! For our industry to better understand the winter crystal phenomenon, we need samples. Please collect them in a ziplock bag or other container, and contact us. Orenda is working in coordination with some leading organizations in the pool industry to figure these crystals out. We will facilitate getting the samples to the right people so they can be laboratory tested. At the time of this article, we still do not know the chemcial composition of all these crystals…nor do we know how many different types exist. Please help us learn more–we will share the information to better help you in the field.

3. Balance the LSI of every pool with crystals in it

The Orenda App should have guided you on what you need to add to the pool. Remember, the pool water should have found equilibrium on its own. We at Orenda believe that a pool with crystals is evidence of calcium being leeched out of the plaster surface due to a low LSI. If you see crystals, it tells us your water was hungry for calcium in the winter as the water got colder, and took calcium from the walls. Do not be fooled by a high pH…even if our Orenda LSI calculator indicates your water should be scale-forming (high LSI). That pH drifted up at the expense of your walls.


It is our recommendation that you manipulate the calculator down to an ideal 7.4 pH on the left, under “current readings”. This will allow you to more accurately identify how much calcium and alkalinity the water really needed before the pH drifted up. You can always adjust pH later…what is important now is building the foundation for LSI balance. And as the water warms up, you can adjust the pH and alkalinity down with acid as needed.

4. Purge the pool with SC-1000 Scale & Metal Control

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SC-1000 is a chelant designed to keep metals in solution. It can gently break down various forms of calcium, including most crystals we have seen. It has a 10.8 pH, meaning it will not further lower your water’s LSI.

After you have tested the water, used the Orenda app, identified how much calcium and bicarb to add (and have successfully added them the right way), the hard work is done. All that’s left is adding SC-1000 to gently dissolve the crystals back into solution. NOTE: if what you have are actually calcium sulfate crystals, SC-1000 alone may not be enough. Calcium sulfate crystals can be a different problem entirely…though they can look similar. Contact us for further guidance if the SC-1000 does not remove your crystals within two weeks.

SC-1000 Scale and Metal Control is a metal chelant. Since calcium is, in fact, an alkali earth metal, SC-1000 can break it down and chelate it. The effect is similar to sequestration, except that most sequestering agents are acid-based. SC-1000 is an alkaline (10.8 pH) product which will not further lower your LSI. Since you’re combatting a low-LSI condition, why would you lower the LSI further?


The best defense against calcium crystals is a good offensive winterization strategy. Such a strategy involves preparing for the winter months by adjusting your calcium, alkalinity and pH in preparation for cold water. We also suggest periodic winter visits to continue to adjust LSI.

If you DO have a pool with crystals, following these four steps should help you rectify the problem as well as you can. Unfortunately, the damage is done, but this four-step procedure should help you mitigate it further. Let us know if you need help in the field. You can request an Orenda visit or training here.

For more on how to start up pools the Orenda way:

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LSI First. Range Chemistry Second.

What if Range Chemistry is the wrong thing to focus on?


In recreational water, range chemistry refers to the textbook ranges for water chemistry. For example, “pH should be between 7.2 – 7.8, and ideally 7.4 – 7.6.” The ranges apply primarily to sanitizer levels, pH, total alkalinity and calcium hardness. There are also maximums (TDS, for example) and minimums (like ORP). If we focus on just those ranges, we are managing water chemistry ‘by the book’, right? But what if range chemistry is the wrong thing to focus on?

Let’s ask the question another way: what is the most unstable chemistry in water? What changes most frequently? The answer is pH, and pH is very important because it affects virtually all other chemistries in water. pH is especially important in chlorine pools, as it dictates the strength of chlorine via Hydrogen dissociation potential. Here’s a chart to remind you.

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The pH determines the the strength of chlorine. Why? Because the Hydrogen in HOCl (the strong, killing form of chlorine) dissociates more and more as the pH rises. This dissociation happens on an equilibrium determined by the pH. If your pH is 7.5, it’s about 50/50 balanced between HOCl and the weaker form of chlorine, OCl-.

Unfortunately, that same concept of dissociation is part of what makes pH so hard to manage. It’s constantly fluctuating in swimming pools; if we are aiming to keep the pH “in range”, we are aiming at a moving target. It’s frustrating, to say the least. And yet, it is common practice in the pool business to juggle acid, bicarb, CO2 and soda ash to attempt to control pH.

If you’re chasing pH, we think you are chasing the wrong thing. Instead, focus on the overall balance of your water, according to the Langelier Saturation Index (LSI).


Three critical, neglected factors of water balance

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Play around with the Orenda App. Watch how each individual factor impacts the LSI.

The LSI has six factors: pH, carbonate alkalinity, calcium hardness, water temperature, Total Dissolved Solids (TDS, including salt), and cyanuric acid (CYA). We are familiar with range chemistry guidelines for pH, total alkalinity and calcium hardness…but what about temperature, TDS and CYA? The APSP recommends the following:

  • Water Temperature: personal preference with a maximum of 104ºF.
  • TDS: maximum of 1500 ppm over start-up levels.
  • CYA: 10 – 100 ppm, ideal range 30-50 ppm.

Do you measure these factors on your pools? If so, how often? They are important factors in the LSI that are very commonly neglected. Play around with our dosing calculator, one factor at a time, and watch the impact they each have on the LSI. You may be startled.

Neglecting half of the LSI only hurts you, your business, and your customers.

Again, LSI first, range chemistry second. If you factor in all 6 components of the LSI, you may discover ways to simplify your job as a pool operator. For example, the calculator teaches us the value of calcium hardness. It buffers your LSI, and it doesn’t fluctuate easily! It is the rock to build your water chemistry castle on. When we change our mindset from chasing a moving target (pH), and instead focus on balancing the LSI, the value of calcium becomes undeniable. Calcium may not buffer the pH directly, but it certainly buffers the overall LSI.

Wouldn’t it be nice to have a foundation of calcium that gets you closer to equilibrium? What could that do for your water? How could that help your bottom line? Imagine how much less you would need to spend on sodium bicarb, soda ash and acid if your calcium level gets you close to LSI balance? You would be making micro-adjustments to your water chemistry…not major ones. The Orenda App calculator taught us this revelation.

Everything gets easier with LSI balance

Let’s take a step back from the chemistry classroom real quick, and put all this message into the real world. We at Orenda have made teaching the LSI a cornerstone of our company’s mission. Why? Because it’s real. It does matter. For too long, we in this industry have been taught behaviors and habits that work for range chemistry management, but ignore other factors of the LSI. Sure, the quality handbooks in the pool business discuss the LSI and its importance…but let’s be real! It’s a tough equation that most people will not do in the field. The economics of managing swimming pools simply do not allow for extended pool visits involving higher math.

That’s why we have so heavily invested in our mobile app‘s LSI calculator. It is a tool so you can calculate the LSI very quickly and easily. AND it tells you how to correct it on your own terms.

We recommend looking at higher levels of calcium hardness in your water so you can see an alternative way of managing your chemistry. See if it works for you. You may find you’re spending a lot less money chasing a moving target, and a lot more peace of mind knowing you are protecting your customer’s pool and equipment from corrosion.

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Honesty in Water Testing

If you’re not testing, you’re just guessing

Water testing is too often rushed and overlooked in our industry. A few months ago, I had the opportunity to take the start up certification course for the National Plasterer’s Council, hosted by Bel-Aqua. As an employee of Orenda, I work with service techs and plaster companies every week. This course was a wonderful opportunity to soak up information like a sponge, and learn more about the business. Granted, I was not actually supposed to take the course (Orenda was a sponsor of the event, and I am not a service tech), but I was invited to participate.

The certification course is taught by the NPC’s Director of Technical Services, Greg Garrett. Not only did Greg cover a broad range of plaster topics, he covered an even broader range of water chemistry. This article shares a few of my takeaways from the class.

1. Accurate water testing is very important

The key word here is accurate.

Do you do initial water treatments for new or re-plastered swimming pools? If you do the initial water treatment, you know how important it is to get the water balanced as soon as possible. So tell me…how can you balance the water if you do not have accurate chemistry readings to begin with? You cannot dose chemicals correctly–even with a dosing calculator like ours.

2. If your water chemistry exceeds the range of the test kit, say so

This point is the impetus for why I wrote this article. The most impactful moment in the entire startup certification course was when we tested water, and Greg Garrett shared a story of his; a hard lesson learned. The example he gave involved a Taylor test kit for cyanuric acid. The test kit has a black dot at the bottom, and you add the prescribed amount of reagent and water until you can no longer see the dot. If the vial is filled to the top line, the reading is 30 ppm of cyanuric acid. If you can still see the dot, the correct answer is “less than 30 ppm”. Here is good video that walks through the Cyanuric acid test I am describing:

After doing the test, Greg, like so many of us would, indicated “0 ppm”. After all, the sample water was completely clear. But since the test kit only went to 30 ppm, that “0 ppm” was assumed, and unproven. Lesson learned.

I share Greg’s story because it is a painful illustration of the shortcuts we in the industry often make. How many of us have ever hurried through testing water? All of us. How many of us have ‘eyeballed’ the line? Or lost count of the drops? Or never calibrate the reagents in the test kit?

I recently made a similar mistake, but thanks to Greg’s story, I caught myself, went back and corrected it. I tested the pH of some tap water in Seattle, and it was clearly above 8.0 pH. But how far above?  I could not tell with the kit. I am so glad I did not report the 8.5 I originally wrote down.

This article is about honesty in water testing. A dosing calculator like ours depends on accurate, honest water testing by you. Otherwise, it’s garbage in, garbage out.

3. Use a better test kit when necessary

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The basic training manual has a wealth of valuable information in it.

According to the IPSSA Basic Training Manual (pg. 161), phenol red reagent (used for testing pH) only shows pH between 6.8 and 8.0. Any pH below 6.8 will look the same as 6.8 (virtually clear). In other words, if the pH is lower than 6.8, you would never know. That’s why using a different test kit is sometimes necessary.

When we visit customers and go to their pools, we test water. If we do not have the necessary kit(s) for accurate water testing, we collect samples in a clean water bottle, and we take it somewhere with a better kit. You may not need to purchase a high-dollar testing machine, as most local pool stores have one. Simply pay for them to test the water for the factors you need.

What is a good option for those of us with color blindness?

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Many of us struggle with red-green color blindness. Can you clearly see the number in this image? If not, consider an electronic test kit. Colorimeters may not be the best option for you.

There are four types of water testing kits most commonly used in the aquatics business.

  1. Color Comparison (test strips or colorimeter)
  2. Drop Count (titration)
  3. Turbidity (like a cyanuric acid test)
  4. Electronic (like a photometer)

If you are color blind (particularly with red-green), consider an electronic photometer to read the results for you. For commercial pools, electronic probes for ORP, pH and chlorine are strongly recommended. Just find the test kit that works for you.

4. Test the fill water

This is one of our most drilled talking points at Orenda. Knowing what water chemistry comes out of the tap is paramount for success. This is especially true for pools with auto-fill or pools and spas that regularly drain some water to dilute. For example, if your cyanuric acid levels are too high, draining and diluting is often the most reasonable option. To balance the incoming water, you need to know what’s in it. Water testing is the best way to know for sure. Remember, if you’re not testing, you’re just guessing.test fill water

Back to those of us who do initial water treatments for startups…accurate water testing of the fill water is critical to success.

Another way to find out what is in the tap water is to request the test results from the water treatment company. Municipal water treatment plants are required by law to test their water, and it is public information. Just ask, and you shall receive. Tell them what you’re looking for too…don’t just ask for pH, alkalinity and the basics. Get everything you may need, including metals and phosphates.

Water testing is the professional thing to do

Customers depend on you to manage water the right way…just like we expect a carpenter to measure before he cuts, and a plumber to seal every pipe watertight. Accurate, honest water testing is the first step in getting there. Thanks for your time.