A cloudy pool is an unsatisfying mess to swim in – and can present you with more than just an aesthetic conundrum. Cloudy pools tend to be filled with biological debris and bacteria, and point towards a lack of proper chemical balance, which is essential for keeping a pool safe to swim in.
Worse yet, a cloudy pool could mean that your water balance is terribly off – which can affect and damage the lining of your pool, lead to nasty staining, and eventually may require serious repairs due to drain clogging and filter replacements.
Just de-clouding a pool isn’t always enough. To really clear up your pool for good, you’re going to have to get to the root of the problem – and embrace the mantra of preemptive prevention, rather than chronic cures, in all things pool maintenance.
Here’s how to clear cloudy pool water.
Why Is My Pool Cloudy?
Cloudy pool water generally means one thing: debris, regardless of whether it’s organic or inorganic. An excessive amount of debris and fine materials in your pool could be the result of:
- Low or poor sanitizer levels (chlorine or bromine, usually).
- A dirty or malfunctioning filter, or a dying pump (low water pressure).
- High amounts of chloramines (and low levels of free available chlorine).
- pH levels and alkalinity that are way off from what they should be.
- A post-storm algae bloom that messed up your water balance.
- Excessive organic debris after neglecting a few landscaping duties (i.e. lots of leaves, flowers, berries, and branches in the pool).
Sometimes, cloudy pool water is the result of one, two, or even three of the reasons listed above. Thankfully, you can de-cloud most pools by going through a relatively easy step-by-step cleaning (and prepping) process.
Steps on How to Clear Cloudy Pool Water
1. Brush, Skim, Vacuum, Repeat
If your pool hasn’t been given its proper share of tender love and care for a little while, then the first task on your list should be to give it a thorough rinse, skim the surface and pool bottom, and run a vacuum over it (either manual or automatic.) You might have to repeat this process at least once or twice, letting the debris settle between cleaning runs to make sure you get most of it out of the pool right away.
If you have bottom drains, you can use these to run most of the debris at the bottom of the pool into the filters.
Do this before you give the filter a deep clean. You want to knock as much excess calcium and debris off the walls as possible, then address the filtration system.
2. Deep Clean the Filter
We need to check the lungs, liver, and spleen of your pool. Your pool’s pump and filters are essential to keeping your water looking crystal clear, as they keep it circulating while catching both the large and small debris in the filter medium. If you haven’t run your pump in a long time, then it might be a good idea to do so. Pool chemicals alone won’t do the job of keeping a pool clean if the debris isn’t getting filtered and cleaned out of the water. If your pump has been running regularly, but the pool is still clouded, then the first thing you’ll want to do is clean out the filter.
Most pool filters utilize either sand, specialized cartridges, or a special kind of extremely fine filter medium called diatomaceous earth (DE filters). The filter of your pool pump will usually be attached right to the pump, and can be opened up with a screwdriver, or via a pair of clamps on the filter tank. Carefully remove the filter and its medium and clean it out as per the manufacturer’s instructions.
Note that different filters require different methods of cleaning. Cartridges can be washed with a high-pressure hose or replaced. Sand and diatomaceous earth filters will need their filter medium replaced every once and a while, and their filter arrays can be cleaned out quickly via the pump’s backwash function and waste valve, or via a deep clean with a hose.
If you’re unsure whether your filter needs cleaning, take a look at the water pressure gauge on your pump. If it’s within normal levels, you’re all good. The higher the pressure, the more clogged the filter. Normal levels will depend on the pump – try to note down what water pressure your pump indicates after a thorough clean, and give it a rinse whenever the pressure spikes way off (i.e. above 25 psi).
3. Shock Your Pool
No, not with electricity. Pool shocks require a large amount of sanitizer (i.e. chlorine), and involve drastically spiking the availability of free chlorine in the pool water. This will help address bacteria and algae that may have been multiplying the pool and sanitize your pool water.
It will also stock up your pool’s chlorine levels, to the point that they keep your pool safe, without irritating your skin.
If you’re worried about excess chlorine, note that a lot of it dissipates via sunlight anyway. You can reduce the dissipation with cyanuric acid but be sure that your chlorine level is at an acceptable point before using it.
The exact amount of chlorine needed for a shock will depend on your pool’s total water volume, usually measured in gallons. It should also be noted that post-algae bloom water cloudiness may require up to three shocks to clear the water up, depending on the type of algae. Always shock your pool right after the sun has set. You want to minimize the amount of sunlight hitting the water while the chlorine shock does its job.
4. Run the Pump
Once you’ve shocked the pool, you’re going to have to run the pump a lot. At least about eight hours a day, and longer if you haven’t used the pool in a while, or if it’s an exceptionally large pool (or a small pump).
Note that pump problems can also lead to cloudy water due to poor pool circulation. If your pump is in need of maintenance, replacement parts, or a total rebuild, be sure to contact a professional.
5. Flocculants and Clarifiers
As your water clears up, you’ll find yourself struggling with diminishing returns in subsequent cleaning sessions as the remaining debris becomes much too fine to properly filter.
You can solve this problem via flocculants and clarifiers. These are specialized pool chemicals that bunch up tiny particles into larger ones, so they get caught in your filter more easily.
6. Redo Your Water Balance
Before you call it a day after a thorough rinse, you will want to preserve the results of your hard work by ensuring that your water balance is right. You will need a couple of pool tests for this, or you can just take a sample of your pool water to a pool professional. In general, they will check for:
- Chlorine levels.
- pH levels.
- Calcium hardness.
- Metal levels, and a few other safety tests.
If your pH is off, your calcium levels are off, or your alkalinity is too high/low, your sanitizer won’t be as effective as it could be, and your water will end up being too basic or acidic, damaging the lining of your pool, causing calcium scaling, and leading to clouding. Proper water balance ensures that your pool is pleasant to look at and nice to swim in.
If you’re struggling with cloudy water, you always have the option of calling the pros. There’s a lot that goes into keeping a pool crystal clear, and a pool professional can help save you a lot of time and quite a bit of money by identifying the core issues, and addressing them efficiently.