Cloudy Water Troubleshooting

A facility having trouble with cloudy water is one of our most common type of calls we get from the facilities that we service.  There are a multitude of causes for cloudy water so we have a few things we do to try to figure out what is happening in, or out, of the pool.  Our focus here is on pools but would apply equally to a spa.   In fact, cloudiness issues will happen much faster in a spa due to the significantly lower volume of water and higher bather to water ratio of use.


Step 1:  We Need DATA!


The first place we start to look begins with the pool chemistry.  Not just pH & Chlorine!  We need the full report.  The technician should be able to tell us the following readings:


  1. pH


A high pH can really cause havoc for pool clarity and can make cloudiness that is caused by particular chemical use even worse.


pH should be maintained between ideal levels of 7.4-7.6.


A low pH may be breaking down metals, minerals, paints, plaster, etc. which may be apparent in the pool water and causing cloudiness.


  1. Total Chlorine


  1. Combined Chlorine


High levels of Combined Chlorine indicate that there has been a lot of demand put on the pool’s sanitizer level.  A high Combined Chlorine reading also indicates that the pool is in need of superchlorination or shocking.


  1. Free Chlorine


A low Free Chlorine reading not only indicates that there is insufficient sanitizer available in the pool but also indicates that there has been something using up the available or “Free” chlorine.





  1. Alkalinity


A high Alkalinity can definitely cause cloudiness in water and should be lowered to appropriate                 levels as quickly as possible – 80-120 ppm in plaster pools and 100-140 in painted or vinyl pools.


A low Alkalinity level usually has a similar effect as a low pH but will also make the pH level of      the pool harder to regulate.


  1. Water Hardness or Calcium Hardness


A high Water Hardness or Calcium Hardness level will typically cause cloudy water.  Unfortunately the only solution to remedy this situation is by changing out some or all of the water.


A low Water Hardness or Calcium Hardness level will have a similar effect as a low pH and low Alkalinity but will also lead to a much faster corrosion rate as water with a low Water Hardness or Calcium Hardness level is classified as “soft” water and the water will tend to leach out metals and minerals in order to achieve a balanced level.


  1. Total Dissolved Solids or TDS (if possible)


                This reading will tell us how much product is dissolved into your pool water.  A good way to look               at this reading is to think of a glass of unsweetened tea.   The more sugar you dissolve into it, the more the Total Dissolved Solids go up.  At a certain point, you will not be able to dissolve any      more sugar into your tea.  The same holds true of your pool water – but on a much larger scale           of volume.  Sometimes you will need to change out some of your pool water.  Be careful though – some pools, by nature of their geographic location, by their makeup water, or if they are using                 technology such as a salt chlorine generator will run a higher than “normal” Total Dissolved          Solids level.


  1. Cyanuric Acid


This is a measure of the amount of stabilizer / conditioner / or cyanuric acid that your pool water has in it.  This is the product that protects your chlorine from being burned off by the UV rays of the sun.   If the level becomes too high though, it may lead to your TDS being too high.  A level between 30-50 ppm is ideal and anything close to 100 ppm indicates that the time is right to change out some pool water.






  1. Salt Level – (if applicable)


                The salt level will help us to determine if you have an adequate level for you salt chlorine             generating system and will also tell us, to some degree, how much of you Total Dissolved Solids      or TDS level is comprised of salt.  This reading helps us to rule out some conditions that could be           contributing to your cloudiness issue.


Knowing the readings above is going to START  to help us identify what may be happening in your pool.


Now that we have a grasp on where your water chemistry is, we can look at some other aspects of what is going on with your pool in an attempt to figure out your cloudy  water.


  1. How many gallons are in your pool?


Believe it or not, some of the trickiest pool issues are caused by the under or over estimation of pool gallons.   To determine your pool gallons simply take the surface area of your pool in square feet  times your average depth times 7.5 and that will tell you your approximate gallons.


Square Foot – Surface Area   X   Average Depth     X    7.5     =    Total Gallons Approximately


Call us if you are having trouble with your calculations.


Adding too much or too little product, due to an incorrect gallons calculation, could be a simple explanation for problems you are having with water clarity.


  1. What is your pool temperature?


A high water temperature can have an adverse effect on certain chemicals that you add into your pool.  Low water temperatures, outside of bather comfort, do not typically have an effect on water clarity – unless the pool gets so cold that it ices over!


  1. How cloudy is “cloudy” – hazy water or fully cloudy as in you can’t see the bottom?


                Is your pool just hazy and looking dull or is it fully clouded like the appearance of skim milk?        Slight differences in clouding level can indicate several different causes of cloudy water.  We will       need to know a level of cloudiness that you are experiencing to point us in the right direction in         establishing the cause(s)







  1. What chemicals are you using on a regular/routine maintenance basis?


                We need to know what chemicals you are using on a regular basis.  This information is going to be very helpful in determining the cause of your water cloudiness issue.


Take chlorine for example.  If you use lots of liquid chlorine for sanitation, your TDS will climb     faster, your pH will tend to run higher, and you may not be keeping up with your sanitizer                  demand.  Conversely, if you use Tri-Chlor sticks or tablets, you will be adding in a much lower pH product but you may be adding it in too slowly to keep up with demand.  Additionally, most Tri-               Chlor users utilize a Calcium Hypochlorite shocking product which is both very high in pH AND in       calcium level.


The additional chemicals that you use regularly will also help fill in the gaps as to what is going    on with the pool.


  1. What type of pool surface do you have?


                Your pool surface may tell us a lot.  Do you have plaster on your pool?  It could be sloughing off                                 into the water as a result of low pH, low Alkalinity, low water Hardness, etc.  Your cloudiness               could be a simple result of the plaster on your pool surface being brushed up into solution.


Is your pool painted?   The same chemistry situation as above will produce similar results with    pool paint.   Oxidizing pool paint will definitely contribute to pool water cloudiness.



  1. Did you just add chemicals? What chemicals did you add?  How did you add them?


                We need to know if you just added anything to your pool, what chemicals they were, and how                 you added them.


A cloudiness issue could be a simple result of adding the wrong chemical, adding the right            chemical under the wrong chemical conditions, adding the right chemical the wrong way      such as broadcasting rather than pre-diluting, or simply adding different chemicals at       the         same time that cause a clouding reaction.


Some culprits that cause water cloudiness and that also fall under “unusual chemical use”            include:    adding calcium hypochlorite by broadcasting (especially in high water temperatures),   adding sodium bicarbonate and calcium chloride at the same time, using an incompatible              algaecide, vandalism acts (motor oil, soaps, paints, etc.), using large amounts of concentrated            phosphate removers, adding in algaecides without lowering high chlorine levels, etc.



  1. Have you had a lot of bathers recently?


                A heavy bather load or use can cause your pool water chemistry balance to spin out of control   just based on sanitizer demand alone.   If your typical erosion chlorinator is set up to dispense at          a level sufficient for 20 users a day, it has no chance of keeping up with a full pool party of 200           guests – unless you turn it up.


Pool parties – depending on the makeup of the guests – are also going to have additional            “demands” placed on the pools.   Users with heavy suntan or body lotion use, users who are            doing strenuous exercise, and users – both young and old – who are not taking their bathroom         breaks outside of the pool are all going to place heavy demands on the pool chemistry and the         pool  filtration – both of which can cause cloudy water.


As a spoiler alert to an age old myth, there is no product on the market that indicates is                 someone is adding their own “contribution” to the pool volume.


  1. When is the last time you backwashed or cleaned your pool filter?


                Check your filter pressure.  A dirty filter is a sure contributor to cloudy water.  As a rule of            thumb, anytime you are seeing 8-10 pounds of pressure over your “clean” filter pressure, it is              time to clean your pool filter.


Dead algae could also still be in the pool water.  Using a clarifier will help it to filter out as will       avoiding the inclination to over backwash.   Your sand filter actually becomes more efficient, up          to a point, the dirtier it gets.   Waiting until the pressure rises 8-10 psi higher than the clean     pressure will make sure you are optimizing your filter performance.   Certain algaes, although                dead, can blow straight through clean sand filter media.


  1. When is the last time you changed your filter media?


As an  average, commercial pools can go up to five years between sand filter media changes while Diatomaceous Earth and Cartridge filters will need much more frequent changes.  Simply put, filter media becomes less efficient and effective over time and needs to be changed.   Don’t just rely on filter pressures or dates either, physically inspect your system and your system’s filter media.  Clumpy sand, hard sand, holes in DE screens, collapsed cartridges, etc. are all signs that it is time for some maintenance.









  1. How long are you running your pump and filter system or What is your turnover and flow rate?


                Commercial pump and filter circulation/filtration systems need to run 24 hours a day and seven                days per week – cut that rate short and you are sure to have issues.


Residentially, I advocate that you run the pool as much as you can afford to but, when properly                sized, no less than what it would take to turn your entire volume twice per day.


Your pool filter acts as the “lungs” of your pool system – you need to move water through the filter to help avoid cloudy water.


Flow rate is the measure of your pool circulation pumps gallons per minute flow capacity.   This                 will be listed as GPM.   To a limit, the higher a GPM, the more water your pump can move.  This          is restricted, of course, by pipe size, filter rates, total head, etc. so an accurate flow rate is     measured on the return side of the pump after all of the pool equipment.   This is critical as      many people incorrectly measure flow rate simply off of a pool pump’s maximum flow                 capability.  This does not accurately reflect flow rate.


Turnover rate is the amount of time that it takes for the circulation system to move the pool      gallons through the filtration equipment.      Commercial pools must meet a standard of         four (4) turns per day or one turn per six (6) hours.  As an example, if your pool is 100,000     gallons, you would need to have a turnover rate of 278 gallons per minute.


100,000 Gallons   ÷  6 Hours   =  16,667 gallons per hour   ÷  60  =  278 Gallons per minute.


If you are not running a sufficient turnover rate, you will most likely have water clarity issues.














  1. What is the condition of your equipment? Have you done any work lately?


Broken sand laterals, leaking pipes, air leaks, hampered pumps, ripped DE grids, used up cartridge elements, etc.  All of these can contribute to cloudy water.


You would not believe how many people do their own sand filter media changes and incorrectly fill up the filter tank all the way to the top.  This is way too much sand and will definitely impact your water clarity.


If you are changing your own sand filter media – go ahead and change the filter laterals and lid gasket as well as the only way to change the laterals is to dig out the sand anyway – since you would have done that in a sand only change, it only makes sense to tackle the laterals as well.


If you change out your multi-port valve diverter gasket, make sure you glue the new gasket in and don’t use silicone adhesive.  Also, make sure you take the ENTIRE old gasket out as any extra material is going to impede the proper performance of the valve.  An incorrectly installed multi-port valve gasket will definitely contribute to water clarity issues.


Your issue may not even be chemical but may just be mechanical.   A run through of all your system components is helpful.


  1. When is the last time you checked your piping?


Broken underground pipes, poorly functioning valves, bypassing Multi-port valves, etc. can also impact water clarity.  If you have bubbles coming out of your returns, you have air coming into your system somehow.


If you are losing more than an evaporation rate of water (more than a ¼ to a 1/3 inch of water per day) you should probably start looking into leaks.


  1. Has it rained recently?


                Rain in and of itself does not cause cloudy water but it will make issues with water chemistry      much more evident and do so much more quickly.  Rain can put a huge demand on sanitizer                levels and on the pool chemical water balance.  Rain also, in some pool situations, can cause    contaminants and material to run-off into the pool which can also cause pool water clarity                issues.





  1. Have you added a lot of makeup water?


                Adding a lot of makeup water can introduce all manner of issues to pool clarity.  Some   municipalities introduce phosphates into their water systems – phosphates can really tie up pool              sanitizers and act as a smorgasbord for algae.


You should always test a sample of your fill water to ensure that you make chemical balance      adjustments to your pool as necessary.



For a complete list of conditions that can cause cloudy water, be on the lookout for or soon to be posting “100 Reasons for Cloudy Pool Water” – coming soon to this website and free for you to download.


Be safe, have fun, and reach out to us – we are here to help.