One of the most important things things that any pool, hot tub or swim spa owner can do is to test their water. This is because testing the water allows you to see how “balanced” your water is.

Water balance is the relationship between different chemical measurements in your pool, swim spa or hot tub water. It is based around how water reacts with other Essentially, water dissolves and holds minerals until it becomes saturated and cannot hold any more. We will refer to this as the water’s “saturation point”. The goal of water testing is to get your water as close to the saturation point as possible.

When the water balance dips below the saturation point, it becomes corrosive. Water that is corrosive will try to saturate itself by dissolving everything it comes in contact with.

When water is above the saturation point, it becomes scale forming. It can no longer hold all of the minerals that are dissolved in it. The excess minerals will then “fall out of solution”, grouping together and forming scale on any surfaces within the water.


  1. To make sure that there is enough sanitizer in the water. Without enough sanitizer, bacteria will begin to grow, making the water unsafe to use.
  2. To make sure that the water is comfortable to swim in. Unbalanced water can irritate your eyes, dry out your hair and make your skin itchy. Balanced water its much more comfortable to be in.
  3. Keeping your water properly balanced will increase the lifespan of your pool, hot tub or swim spa’s equipment.
  4. Keeping your water properly balanced will save you money in the long run.

While the first two points are more or less self explanatory, the last two require a little more explanation.

Increased Lifespan

For most people, hot tubs, swim spas and pools are a big investment. For that reason, you should protect that investment and ensure that it lasts for as long as possible. Maintaining proper water balance is by far the best way to ensure extend the life of your pool, hot tub or swim spa.

Corrosive water rusts any metal components within it, notably pumps and heaters. It also causes plastics to become brittle, degrades rubber o-rings and can even cause pits to form in the finish of concrete pools!

Scale forming water deposits calcium scale on any exposed surface. This can be especially harmful if your pool or hot tub has a heater or salt system. A layer of scale as thin as a single piece of paper can reduce the efficiency of your heater or salt system by 50%! This causes them to work harder than they need to and greatly reduces their lifespan.

Well balanced water has none of these issues and can seriously prolong the life of your pool, hot tub or swim spa.

Saving Money With Regular Water Tests

Regular water testing can also save you money in the long term. While it may sometimes feel like a waste of money to keep adding chemicals to your water, these costs are greatly outweighed by the costs associated with unbalanced water. These costs include:

  1. Reduced equipment life. As we just saw, unbalanced water can cause serious damage to the equipment of your hot tub, swim spa or pool. The cost of prematurely replacing this equipment, especially things like pumps, heaters and salt systems, greatly outweighs the cost of maintaining proper water balance.
  2. Treating problems. The cost of properly maintaining your water is a fraction of the cost of fixing problems like green or cloudy water. Fixing these problems generally costs more than the balancing chemicals required to prevent them. You are also not able to use your hot tub, pool or swim spa while treating these problems, which kind of defeats the point of buying it in the first place!
  3. Increased sanitizer usage. The effectiveness of sanitizers (chlorine or bromine) changes with the pH of the water. If your pH is off, you will need to use more sanitizer because it is working less efficiently than it would be in well balanced water.


Most people look at crystal clear water and assume that their water balance must be perfect. As we’ve previously discussed however, clear water doesn’t always mean good water. In fact, water that looks clear can sometimes have serious problems.

While clear water is usually a good thing, it can also be an indication that your water is acidic. Remember that acidic water is below the saturation point. It can therefore hold a lot of minerals in solution without the water turning cloudy. While this keeps your pool, hot tub or swim spa looking good, it also reduces the lifespan of the equipment.

Without testing it, there is also no way to know if your pool hot tub or swim spa has too much sanitizer. Maintaining a good sanitizer level keeps away algae and ensures that the water is safe to swim in. Too much chlorine, however, can cause a lot of wear and tear on the equipment (pump, heater, pool ladder etc.) of your pool, swim spa or hot tub.


We strongly recommend testing your pool or hot tub water at home at least 2-3 times per week. Pay close attention to your pH and chlorine/bromine levels and adjust as necessary.

If everything looks good on your home tests, we recommend getting your hot tub or pool water professionally tested at least once per month. If you encounter problems such as consistently low pH, cloudy water or green water, you should bring your water in to be professionally tested as soon as possible. Problems like these will only get worse with time and are much easier to treat if caught early.


If you can test the water at home, why even get a professional water test? Professional water tests are much more accurate and thorough than home tests.

While home testing kits will typically only test for sanitizer, pH and alkalinity, professional water testing systems also test for things like:

  1. Stabilizer. Stabilizer is added to pools to help prevent the chlorine in them from being destroyed by the Sun’s UV radiation. The less stabilizer a pool has, the more chlorine it goes through. Too much stabilizer and the pool water goes cloudy.
  2. Calcium Hardness. The amount of calcium in the water. Calcium plays a big role in the saturation of water. Adding calcium can help increase the saturation of the water and lessen the chances of it turning corrosive. Too much calcium however, can cause serious scaling issues.
  3. Metals. Metals can be introduced from outside sources like well water, or from metal elements within the water (commonly heaters, pumps and pool ladders) corroding due to acidic water. Once dissolved into the water, metals can cause the water to change colour or metal stains to appear on surfaces.
  4. Phosphates. Phosphates are essentially algae food. The more phosphates that are in the water, the easier it is for algae to grow, sometimes even when there is sanitizer present in the water.

The extra tests and improved accuracy of professional water testing gives you a much more complete picture of the overall health of your pool, swim spa or hot tub water. This allows you to fix potential problems before they arise and makes it much easier to keep your water in balance.

We recommend professional testing once per month as water balance does not stay constant. Almost everything that goes into a hot tub, swim spa or pool affects its balance. Weather, chemicals, bathers, fill water and even dirt brought in by the wind all affect the water in some way. Regular water testing allows you to stay on top of these changes and keep your water balanced over time.


  • Get your water sample while the hot tub, swim spa, or pool is circulating. Slight differences exist in the balance of still water. Circulating the water evens out these differences and gives you a better idea of the overall balance of the water. If you’re testing your pool, make sure that the pump is on and circulating the water before taking a water sample. For hot tubs and swim spas, turn on the jets before taking your water sample.
  • Take your sample from water that is 12”-18” below the surface (about elbow deep). Water at the surface interacts with air, which affects it’s balance. Water on the surface therefore does not give you an accurate representation of how well balanced the water is overall.
  • Check the expiry date on your reagents. Water testing reagents generally have a shelf life of around 1 year. The older a reagent gets, the less it will change colour. Old and expired reagents will therefore always display low level readings, causing you to treat for a problem that doesn’t exist.
  • Don’t test water near the return jet of a pool. The chlorine level coming out of a pool return jet is generally a lot higher than in the rest of the pool water.

The Spa Shoppe

(905) 666-5333

1545 Dundas St E
Whitby, ON L1N 2K6



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