3 Reasons Why Your Pool Water Looks Clear, But Feels Slimy (How to Fix!)

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Owning a pool provides countless benefits. It’s a great way to keep cool in the summer without having to travel to a beach. It can also provide an easy means to host get-togethers with family and friends.  

However, a pool is not always easy to maintain as it requires careful attention in keeping the water and pool equipment operating at ideal levels.  

While many issues, such as murky water, can be visually seen from afar, there are other cases where you may actually have to feel the water to notice something seems a bit off.  Maybe the pool water is clear but feels slimy.  Or, maybe it feels oily or sticky?  

If the water looks clear, but feels slimy, this is definitely a reason to pause and take some time to investigate.  The last thing anyone wants is to have a minor issue transform their pool into the dreaded green swamp.

Let’s dive into some of the causes for these situations, along with some quick fixes.  

Why Pool Water Looks Clear, But Feels Slimy

There are several main reasons why your pool water may feel slimy, even though the water looks sparkling blue:

Early Signs of Algae

One of the most common reasons why your pool water might feel slimy is due to the infamous algae.  While most people envision a typical algae bloom being visually colorful –such as green, pink, yellow, or brown– the early stages may be almost invisible.

Algae are microscopic organisms that are less visible when they have yet to fully bloom.  Some of the first signs of algae growth may be slimy feeling surfaces in the pool.  

Eventually, if left untreated, the algae will probably start becoming visible pretty quickly –potentially within a day or two.  The pool may start to look a bit hazy and then could start to show the green growth.   

High Levels of Calcium

While calcium is an important attribute for healthy pool water, like anything it must be kept at certain levels.  Calcium helps keep your water at the appropriate hardness.

The proper calcium hardness (CH) depends on the type of pool and overall water chemistry, but in general a range of 200 to 400 ppm is recommended.

High levels of calcium can form a hard and slippery film on pool surfaces.  In some cases calcium build-up may appear as a white film, but in other instances it may not even be visible.

CH should be tested at a regular interval, although it’s not prone to change as quickly as sanitizer, pH, and alkalinity levels. 

High Levels of Total Dissolved Solids

Total dissolved solids (TDS) are the total amount of organic and inorganic substances dissolved in water.  This can include minerals, salts, lotions, body oil, and other compounds.

Ideal levels of TDS in a swimming pool can vary, but often it’s recommended keeping them below 2000 ppm.  

As TDS increases, scaling on the pool surfaces may occur causing them to become slippery or slimy.  Higher TDS can even cause the water to become cloudy.

How to Fix Clear Pool Water That Feels Slimy

As we’ve seen, there are several factors when it comes to pool water feeling slimy.  That means your first step in resolving the issue is to identify the cause.

Step 1 – Identify the Cause

Start by checking the water chemistry of your pool.  Some of the easiest measurements to start with are free chlorine (FC), pH, and total alkalinity. If FC is low or non-existent, it’s very possible that you may be seeing an initial outbreak of algae.

If you have plenty of chlorine, then it’s probably worth moving onto the calcium hardness (CH) testing.  Many of the mid-tier pool test kits include this CH testing.  High levels could be your culprit of the slimy-feeling water.

Even if you don’t have a test kit that includes CH, you may be able to see signs of white scaling around the pool surfaces, which can be indicative of high levels.

Lastly, if both FC and CH checkout OK (had to keep the acronym flow going there), then it may be worth testing the TDS.  Measuring TDS is often not included in many pool test kits, but you can purchase a TDS test on its own.  Alternatively, there are also TDS meters that can be purchased, or your local pool shop may be able to test it.

If TDS measures high, then that could be the smoking gun that’s causing your issues.

Step 2: Restore the Balance

Once you’ve identified the cause of the slimy water, it’s time to restore the balance.  Here are solutions to a few common problems.:

Low FC

If you’ve noticed a slimy feeling in the water and measured low FC, then it’s best to shock the pool quickly.  This will stop any algae growth in its tracks.  

Various forms of chlorinated shock exist, but ultimately you’ll want to boost chlorine levels up to 5 times the normal chlorine level.  Depending on your stabilizer level in the pool, this could require FC of near 30 ppm to fully eliminate growth.  

Additionally, adding an algaecide as part of your maintenance routine can help prevent algae growth from the start.

High Calcium Hardness

There are two common ways that most pool owners reduce the CH levels.  

The first method is to partially drain and refill the pool with fresh water that has lower calcium levels.  If your source water has high calcium to begin with, then you’ll want to skip this option.

A second option is to use a sequestering agent.  The sequestrant can be purchased, and will bind to calcium ions in the water.  

It’s important to know that sequestering the calcium does not actually remove the calcium from the water, but instead keeps it suspended off the surfaces. This will eliminate the slimy feeling on the surfaces that you may have noticed.

Periodic maintenance additions of sequestrant may be required in order to keep the calcium suspended.

High Total Dissolved Solids

Unfortunately, there’s no magical product that can reduce TDS levels in your pool.  

The quickest way to lower the TDS is a partial drain and refill of your pool with fresh water.  Topping off the pool with fresh water after evaporation can also slowly knock the TDS down.

A more expensive option would be to schedule a service call to have your pool water run through a reverse osmosis filter that can actually remove the TDS from the water.

Step 3: Clean the Pool Surface

While built-in pool skimmers often do a great job in keeping the surface of the water clean, sometimes it just can’t keep up.  This is particularly true during windy days when pollen and leaves are floating through the air.

If you see excess debris on the surface of the pool, it’s best to manually remove it with a skimmer net before it sinks to the bottom.  Organic debris can quickly eat through chlorine levels and increase the likelihood of slimy growth.

Step 4: Scrub and Vacuum the Pool

It’s essential to routinely scrub the surfaces of the pool, including walls, floor, and corners.  This will help loosen any growth that could be causing an icky feeling in the water.

Once the surfaces are scrubbed, this will also help the chlorine more quickly kill off any algae.

Allow a bit of time to pass so that any loosened debris can float to the bottom. Then, you can vacuum the pool to get rid of the unwanted contaminants.  

Step 5: Maintain the Water Circulation

Water circulation is key to keeping the pool clean and preventing water from turning slimy.  

It’s important to allow your pump to run long enough so that the entirety of the pool can be filtered at least once a day.  You can use a pool noodle to help you figure out just how long it will take to achieve a turnover each date.

Keeping the filter clean will also maximize circulation and will minimize the growth of algae.

Reasons Why Your Pool Water Feels Oily

While slimy water is more common, some swimmers may describe the water as feeling oily.  Oily-feeling water may look clear or could look hazy, depending on the underlying cause.

Here are a few reasons why your pool may feel oily:

  • High levels of organic matter, such as body oils and lotion.
  • High total dissolved solids
  • High pH levels

You can use similar steps previously described for slimy-feeling water to get rid of this oily sensation.  To lower the pH of water, you can use muriatic acid or pH reducer from a pool store.  

Showering prior to using the pool can help keep organic buildup to a minimum.  

Reasons Why Your Pool Water Feels Sticky

If the pool water makes you feel sticky after taking a dip, it might be due to one or a combination of the following:

1 – High Chlorine Levels

While it may seem surprising, high levels of chlorine can cause the water to feel sticky. This can also cause skin and eye irritation.

It’s impotant to allow chlorine levels to return to safe levels before entering the water.

2 – Plasticizers

Plasticizers are usually added to vinyl liners made for pools. These substances may gather on the liner’s surface due to the absence of water circulation.

3 – Dead Algae

The remnants of dead algae in a pool could leave the water and surfaces feeling sticky.  Dead algae often is brown and will sink to the bottom until it is vacuumed up.  

If fending off an algae attack, it’s key to vacuum the pool after the algae is dead.  

4 – High pH Level

If the pool’s pH level is too high, it could cause scaling of surfaces leading to that sticky feeling.

You can use muriatic acid or pH reducer to bring the pH back to normal levels of 7.2 to 7.6 ppm.

When Is the Best Time to Shock Your Pool?

To keep a pool clean and free from contaminants, maintenance experts suggest shocking your pool in the following situations:

In the Evening

It’s best to shock your pool after the sun has set.  This is because shocking in the evening will allow a fair amount of time for chlorine levels to return to a safe level for swimmers.

Shocking when the sun has set will also prevent excess burn off from the sun to maximize the effectiveness.

In Summer

It’s more fun to swim on sunny days, but your pool is more prone to algae and other contaminants when the weather is hot. 

You’ll likely need to increase the frequency of shocking the pool during the midst of summer.  

After a Storm

Heavy rains and strong winds may dilute your chlorine levels and could knock in debris.  Cleaning and shocking it after a storm will ward off any unwanted growth.  

Final Takeaway

If you’re wondering why your pool water is clear but feels slimy –or perhaps it feels sticky or oily– it’s often an early sign that trouble could be brewing.

Your first step is to investigate the cause.  Measuring the water chemistry is a starting point, along with a thorough inspection of pool surfaces for signs of scaling.

Once you’ve determined any deficiencies in the water balance, you can take appropriate steps to fix the issue.  

Many times the slimy feeling is the early stages of algae, which can be taken care of by shocking the pool.  Other times, it could be high levels of calcium or TDS.

To help keep the water feeling as good as it looks, clean your pool regularly, keep the water balanced, and maintain the water’s circulation. 

Another oddity that some swimmers may notice is that the water tastes bad –this can actually be caused by some of the same water imbalances that cause it to feel slimy!

Happy (Slime-Free) Swimming!

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