How To Clear Cloudy Pool Water (3 Easy Methods)



I hate cloudy pool water as much as I hate cloudy lemonade (which is weird, because I really like regular lemonade). They’re ugly, dirty, and generally not ideal for swimming thanks to a number of potential health risks.

The worst part? Cloudiness can strike your pool in a matter of hours, leaving you scratching your head as to what exactly went wrong.

In this article, I’ll walk you through the exact steps to identify, clear and prevent a cloudy pool for both inground and above ground pools.

Need a quick answer? The cause is either chemical imbalance, circulation/filtration issues, or environmental effects. To fix it, you’ll first want to test your pool chemistry to make sure everything is in balance, then throw in some clarifier or flocculant to clump the debris. Your filter will take care of the clumps and voilà… clear water.

Wait, Just How Cloudy Is Your Pool?

“Cloudy” is a pretty vague term, and you should know that there are different stages of cloudy pool water. And yes, it goes from bad to worse.

Personally, I’d break cloudy water into three categories:

  • Flat. The least severe form, in that your pool water still has it’s color but it doesn’t have the sparkle it once did.
  • Hazy. The water is starting to lose it’s color and it’s now difficult to make out small details on the pool floor.
  • Milky. The water is no longer translucent, meaning the pool floor is not visible at all. This is pretty much as bad as it gets.

What Causes Cloudy Pool Water?

There are a number of reasons your pool water can become cloudy, and understanding the potential cause will not only help you fix it, but also prevent it in future.

So let’s talk about ways to fix the root of the problem before treating the symptoms — because we’re not about to slap on a bandaid and call it day.

Here we go…

Cause #1: Imbalanced Pool Chemicals

If, like me, you didn’t pay attention in your school chemistry lessons, it could just be a chemical imbalance in the water. (In fact, this is one of the most common causes of cloudy water.)

Having too much of one chemical or not enough of another is your fast-track ticket a cloudy pool, so checking your pool chemistry for high pH, total alkalinity and chlorine levels is always a good place to start. Balance is key.

Got a cloudy pool after opening? If you’ve peeled back that pool cover after a long winter only to find a mist of cloud has found itself into your pool, it means you didn’t winterize correctly. In that case, you’d need to go through the same steps of testing and balancing I’m about to go over.

Is Your pH Level Right?

The best pH level for your pool water is somewhere between 7.2 and 7.6 on the pH scale, which happens to be slightly alkaline.

Your water won’t turn cloudy simply because your pH level is outside of this range, but it will prevent your pool chemicals from doing their job properly, causing particles to linger which will eventually lead to a cloudy pool.

Measuring your pools pH level is pretty straightforward using a decent test kit, so make sure you do that weekly to stay on top of any sudden changes.

If you’re looking for a reliable pool test kit, I recommend this one:

AquaChek 7-Way Pool and Spa Test Strips - Silver Pool Test Strips For pH,...
AquaChek 7-Way Pool and Spa Test Strips - Silver Pool Test Strips For pH,...

    Is Your Chlorine Level Right?

    You need chlorine in your pool to fight off nasty bacteria and other microorganisms, but the amount you use shouldn’t be overlooked.

    The “sweet spot” is between 1 and 3 ppm (parts per million). This keeps your water clean but also prevents it from becoming cloudy — assuming everything else is balanced.

    Exactly how much depends on how often your pool is used, how busy it gets, and the weather it’s exposed to. (The sun will “cook” your chlorine, turning it into gas and causing your chlorine level to drop faster.)

    Is your pool cloudy after shocking with calcium hypochlorite? Not to worry, this is normal and should resolve itself in a day or so as the chlorine level drops. Just keep your filter running in the meantime. If it doesn’t clear up, either your filter-system is compromised, the rest of your water chemistry is out of whack, or you’re using some cheap-ass, low-grade shock.

    Is Your Alkalinity Level Too High?

    Alkalinity—or Total Alkalinity—is a pH buffer, meaning it absorbs changes in the water in order to keep your pH level stable. If your alkalinity it too high, however, it can cause your water to turn cloudy.

    Once again, most pool test kits will allow you test for alkalinity, and you’ll typically want this to be between 80 and 120 parts per million (ppm), or 100 and 140 parts per million for painted, vinyl, and fiberglass inground pools.

    You can use muriatic acid (hydrochloric acid) or dry acid (sodium bisulfate) to lower alkalinity, though dry acid has some unwanted side effects.

    Is Your Calcium Hardness Too High?

    Calcium hardness is a measure of how much calcium is in the water, with the recommended range being somewhere between 200 ppm to 400 ppm.

    While low calcium hardness levels can cause damage to your pool fittings, it’s the opposite side of the spectrum you need to be concerned with here. High calcium hardness leads to excess calcium, which eventually results in scaling and cloudy water.

    Unfortunately, most test strips won’t include calcium hardness, so you’ll want to use a liquid test kit instead. (Again, I highly recommend this one.)

    If you find that you have high calcium hardness levels, the best option is to drain some of your pool water and refill it. If you can’t do that for some reason, you can try using pool flocculant to clump the excess calcium, but it will require a manual clean-up afterwards.

    In The Swim Super Floc Pool Water Clarifier
    In The Swim Super Floc Pool Water Clarifier

      Cause #2: Circulation & Filtration Issues

      Pool water that isn’t being properly circulated is always at risk of becoming cloudy water.

      That’s because circulation pushes your pool water through your filter system, so without it, the filter can’t work it’s magic and keep your water squeaky clean.

      There are a few moving parts to this, so let’s go through them.

      Is Your Pump Powerful Enough?

      A pool pump is a core part of your filtration system as it cycles your water through the filter in order to remove debris and maintain circulation, this prevents the water from stagnating which eventually breeds other problems.

      With that in mind, you need to make sure your pump has the ability to cycle the entire contents of your pool (turnover) at least once per day. What’s more, you’ll need a pump that can complete a turnover in an 8 hour period.

      The speed at which a pump completes a turnover is based on two factors:

      1. The volume of water in your pool (use this calculator)
      2. The flow-rate of the pump itself (this will be listed in the product specifications of any pool pump)

      Note: Flow-rate tells you how many gallons of water pass through the pump each minute, and it’s appropriately measured in gallons per minute (GPM).

      To properly size your pump, divide your water volume by 8, then divide again by 60. What you’re left with is your pools required turnover rate in GPM. The flow-rate of your pool pump should be at least the same.

      Is Your Pump Suited To Your Filter?

      You wouldn’t put all that effort into correctly sizing your pool pump only to neglect your pool filter, would you?

      If your pump is too powerful for your filter, it will end pushing more water than your filter can handle. This bottleneck not only prevents the water from being properly cleansed, but it can also cause physical damage to your filtration system.

      Pool filters share a similar rating system to pool pumps as they’re rated in gallons per minute (GPM) per square foot. Again, your filter should have at least the same rating as your pool pump.

      Are You Maintaining Your Equipment?

      This is one of those “duh!” pieces of advice that most people skim over, but you’d be surprised at how often basic pool maintenance is overlooked.

      Your pool equipment is your first line of defence, so making sure it runs effectively should be at the top of your list. That includes identifying and remove blockages, regular cleaning and timely part-replacements.

      Cause #3: Environmental Effects

      If your cloudy water has nothing to do with the chemicals or the filter system, then the only reasonable explanation left is that it’s being caused by the surrounding environment.

      Yep, Mother Nature can be a real b*tch sometimes. Here are some of the likely environmental causes:

      Leaves & Small Debris

      While leaves will be easy enough to remove before they dirty up your water, it’s really the build up of smaller dust and particles that can get you into trouble.

      Small Animals & Insects

      Insects and small animals will always find their way into your pool eventually, but the biggest things to keep an eye out for is droppings, particularly bird poop. (Yeah, I said poop.)

      The Dreaded Algae

      Insects and small animals will always find their way into your pool eventually, but the biggest things to keep an eye out for is droppings, particularly bird poop. (Yeah, I said poop.)

      Surface Runoff

      Heavy rain can cause water to accumulate on the ground, in some cases making it’s way to your pool bringing plenty of other nasties with it (depending on your pool type and setup).

      Don’t forget… On top of all this, you also have to account for the countless things that we humans take into the pool every time we decide to go for a little swim. That’s right, you’re not as clean as you like to think. 😉

      How To Fix Your Cloudy Pool

      Now that we’ve looked at (and hopefully identified) the potential cause for your cloudy pool water, let’s talk about clearing it up.

      As you might expect there are a few ways to fix cloudy pool water, so let’s break them down one-by-one.

      Method #1: Using Pool Clarifier

      Swimming pool clarifier is a chemical that’s used clean up your pool water, and they’re pretty damn good at it too.

      How do they do it?

      Well, it works through a process called “coagulation” and it’s really not as complicated as it sounds.

      Cloudy pool water is essentially a buildup of tiny particles, and your filter can have a difficult time catching those because of their size — but that’s why coagulation is useful.

      Coagulation aids your filter by clumping those smaller particles together, making them much easier to remove. (If you want to nerd out on the specifics of how this works, read this.)

      Method #2: Using Pool Flocculant

      When it comes to pool chemistry, pool flocculant (or pool floc) works similarly to pool clarifier in that it clumps those pesky particles together to make them easier to remove, except it does have one distinct difference.

      Rather than work with your filter to eventually remove the particle clumps, flocculant attracts them to the bottom of your pool where they’ll need to be removed via vacuuming.

      There’s a few important points to note about this process:

      • Manual: You won’t be able to use an automatic pool vacuum to do this, it’ll have to be done manually.
      • Water: As you vacuum out the cloud particles, you’ll naturally lose a considerable amount of water, so it’s a good idea to keep the hose running as you’re doing this.
      • Filter: It should take around half a day to clear out the debris from the bottom of your pool, during which point your filter should be turned off

      Why would anyone choose to go this route?

      Well, simply put, it clears your cloudy pool water fast. If you’re in a hurry to clear up your cloudy water for whatever reason, this is the way to go.

      Method #3: Assisting Your Filter

      The last method is just letting your filter clean up the mess.

      We all know how important filters are for swimming pools, but we also know they can’t function properly without a bit of help from time to time.

      A good example of this is your pool’s skimmer, which works in harmony with your pool filter to siphon off debris from the surface of your pool. (I know, it’s like magic or something.)

      The problem in this case is, however, is that the cloud particles won’t be floating to the surface. Not without a little nudge, at least. *wink wink*

      You can do this in two ways…

      #1: Stir It Like A Cup Of Tea

      This one involves getting your giant spoon out and stirring your pool like the BFG. Just kidding. (But seriously, you could do that if you had a giant spoon.)

      Ideally, though, you’ll want to use a pool brush to get the particles in motion and eventually pushed to the top pool. That way, your skimmer and filter can do their thang.

      #2: Suck It Up With Your Drains

      If you have an inground pool with a bottom drain, you do have another option that’s less labour intensive.

      Your bottom drain will allow your filter to pull water from the pool floor, at the same time sending a flow of clean water to the surface — essentially giving you the same effect.

      If you don’t have a bottom drain, there’s a little hack you can use that also works with above ground pools.

      Quick Tip: You can simply connect your manual vacuum cleaner as usual, but instead put the vacuum upside down in the middle of your pool, forcing it to pull water from the bottom. What a ninja!

      That’s A Wrap!

      Nobody likes waking up to cloudy water in their pool, but it doesn’t have to be quite as devastating as many first-timers believe.

      The methods outlined above are by the far the easiest and most affordable ways to clear a cloudy pool, and also prevent it from happening again the future.

      Good luck and happy swimming!

      Categories: Pool Care, Pool Problems