As a saltwater pool owner, you get used to certain things over time and learn how to spot trouble in the pool before it gets out of hand. Whether it’s a weird sound coming from your pump or something concerning the color and clarity of your pool water, over time you’ll learn to troubleshoot things early so you can fix them before it becomes a bigger issue.
Cloudy pool water is often the first sign you see when you are running on low or no chlorine. It might be because the salt chlorinator has a problem or the setting is too low and you’re not producing enough chlorine. It may also be due to sudden rainfall that has dropped the chlorine level below the ideal range or a very hot sunny spell that has killed off free chlorine and left the water vulnerable.
And if you notice the water turning green and see a similar green color attaching itself to the pool floor and walls, you have an algae problem which can also occur due to lack of chlorine.
Chlorinator Problems
In my experience with our old first generation salt chlorinator from Lectrinator, it was a very basic model with no monitoring of any kind and had only several green lights (green was good and meant things were working) and several red lights (red was definitely bad). So when I walked to the pool pump area and saw a green light, I was happy. But when I saw the red “check cell” light up, that meant I most likely needed to buy a new salt cell because the current one had broken and our chlorinator was no longer generating chlorine.
Whether you have a dead salt cell or another technical problem with your chlorinator system, once it stops producing chlorine, you’ll see the pool water get cloudy within several days or less. At that point you have to replace or fix the problem and in the meantime, probably manually add chlorine to the pool to keep the water sanitized.
But if your chlorinator is producing chlorine and you’re getting cloudy water, it’s likely that you have low chlorine and may need to increase the output on your chlorinator. First do a full test of pool chemistry and make sure everything is in line and then act accordingly. Check out this page on pool chemistry to learn more before you start dumping expensive chemicals in that you may not need.
Environmental Effects
When you get heavy rainfall, it can mess with pool chemistry and lower your chlorine levels while pulling other aspects of the pool water out of line, too. I’ve seen heavy rainfalls over night where I get up the next day and the pool level has increased by several inches to the very top of the skimmer. At that point I needed to drain water out of the pool which has the effect of removing salt, chlorine and other chemicals which then have to be replaced.
The sun can also play havoc with pool chlorine levels. Direct sunlight kills chlorine and of course in the summer, we all want nice hot, sunny weather so we have an excuse to use our pool! Using a solar blanket not only helps to retain heat in your pool, it also reduces water evaporation. It also protects the pool water from chlorine-killing sun rays when you aren’t using the pool while significantly reducing the evaporation level, too.
So when you leave your pool uncovered at all times, you lose water, lose heat and also kill your chlorine quicker which means you’ll have to run your chlorinator longer which reduces its lifespan. Whew.
And if you check out the pic at the top of this post, you’ll see a view of my pool and landscaped backyard. We have a significant number of bushes, flowers, trees, shrubs and soil within a few feet of each side of the pool. When any of that falls into the pool, it helps to pollute the water.
Bottom line: The more sun and rain you get and the more pollutants that fall into the water, the greater the chlorine requirements to keep your pool crystal clear.
Pool Usage
The more you use your pool, the greater the chlorine requirements. Humans bring sweat, body oil and other stuff into pools which contaminate the water. And if you have a dog who likes to swim or have birds flying overhead using your pool as a toilet, that increases the chlorine needs even more.
Modern chlorinators like our Hayward system have a special Super Chlorinate feature to help your pool get ahead of chlorine requirements before heavy usage. So if you knew on Friday that you were going to have people over on Saturday for a pool party, it’d be a good idea to use the Super Chlorinate feature for perhaps 8 hours overnight on Friday to manually bump up the chlorine output. By the time your friends arrive to swim on Saturday, the chlorine level will be higher than usual to deal with the increased swimmer load. By the time you’re done swimming, much of the free chlorine may have been used up, bringing it back down to a normal level.
This prevents your pool from going cloudy. If you don’t do this ahead of time, you increase the chance you will face cloudy water the day(s) after your party.
Algae
I’ve written articles on both green and mustard/brown algae. Algae occurs in a pool when chlorine levels are low. Keeping chlorine levels within range will keep algae at bay even during the hot summer pool season.
Algae can also take root when there isn’t enough water circulation (you may not be running your pump enough during the day) and improper filtration (the filter mediums might be dirty). Ensure you are running your pump long enough each day given your pump throughput and pool size (gallons/liters) and that your filtration medium (you will either have a cartridge filter, sand filter or D.E filter) is clean and doesn’t need to be replaced or rinsed.
Summary
The main reason your pool water gets cloudy is due to low or no chlorine. This in turn is largely due to a malfunctioning chlorinator, dead chlorinator cell which needs to be replaced or the setting on the chlorinator is set too low (ie. you’re not producing enough chlorine).
Pool water chemistry can quickly get out of whack when you have significant rainfall or strong direct sunlight and when you have a large bather load in your pool, too.
Regularly monitor pool chemistry and test your water weekly, more frequently if necessary. Learn to identify issues in your pool early before they become a bigger problem.
