How To Lower Chlorine In Pool 5 Step Guide

chlorine test tube in a blue swimming pool

If you have had a pool for any length of time, the inevitable will happen.  Maybe you were distracted while you were pouring in the chlorine, or you put tablets in the skimmer and weren’t thinking.  Whatever the case, you’ve over chlorinated and now you need to figure out how to lower chlorine in pool.  So what do you do?  In this article we go over the various ways you can eliminate chlorine from the pool.  

When To Lower Chlorine In Pool

Making sure your pool is safe for swimming includes making sure you have chlorine in the pool. However, if your chlorine level is above 5 ppm, it really should not be used for swimming until the level comes down.

How To Lower Chlorine In Pool Using Common Sense

First, stop adding chlorine to the pool.  This may sound simple, but you may be wondering how.  If you have an automatic chlorine feeder located at the equipment, you will have a valve you can turn to shut off the water flowing over the chlorinator.  If you have chlorine tablets in the skimmer, go grab a 5 gallon bucket (an old empty chlorine bucket is great for this), pull out the skimmer basket with the chlorine tablets and dump them into the bucket.  Leave the uncovered bucket someplace outside where children and pets won’t get to it, and let the tablets dry out.

If you have a salt system, go to the control panel and turn the salt system off.  It’s not uncommon for salt chlorinators to super chlorinate the pool when they start to malfunction.  It sounds counterintuitive at first, but once you realize how these systems work, it makes sense that they could over chlorinate the pool without much effort.

Next, if you have an automatic cover, or solar cover on the pool, retract or remove it.  Sunshine is the best friend of excess chlorine removal.  Normally, you’d keep the pool covered to reduce the amount of chlorine needed in the pool.  In this case, since you’ve over chlorinated the pool the sun is your best bet to remove chlorine. You will have to wait some time, generally a few days depending on how much chlorine you need to remove.

#1 Best Way How To Lower Chlorine In Pool

If you still have too much chlorine, or your chlorine level very high there is another solution.  If your chlorine level is over 20 ppm, you may want to try chemical chlorine neutralizer, like sodium thiosulfate

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Sodium thiosulfate is an effective neutralizer of chlorine, but only needs to be used if you have an extremely high level of chlorine.  It is also used when you need to remove all chlorine from the water prior to draining down the pool for pool removal, or for seasonal drain down.  Depending on where you live, this may be required to protect the environment.  Watch your dosing and follow the instructions carefully.

Most Drastic Way How To Lower Chlorine In Pool

Now we’ll explain the most drastic measure you can take to lower your chlorine level immediately. This is by draining down your pool and refilling.  We do not recommend this.  First, you are sending super chlorinated water out into the environment or into the sewer system.  Second, by draining down your pool you are going to need to spend money to get that water back into the pool, either by using your hose or paying for water to be delivered.  In our opinion, either wait it out, or add some sodium thiosulfate.

blue glove holding 4 large white chlorine tablets above a pool showing how to lower chlorine in pool by reducing the adding schedule

Find The Culprit For Why You Had To Lower Chlorine

Once you’ve successfully solved how to lower chlorine in pool, and your pool is returned to normal, it’s a good idea to revisit why the chlorine level was elevated to begin with.  If it was intentional and you were shocking the pool to eliminate a mustard algae bloom for example, you had a good reason.  But if you had elevated chlorine levels and you were doing nothing out of your ordinary routine, your routine needs to be looked at and changed.  Start by testing your water twice a week for a while and make small adjustments whenever you need to.  Take extra precautions when adding any chemicals and always make sure you are keeping safety as the first priority. 

How To Lower Chlorine In Pool Summary

Now you have a handful of ways to lower the amount of chlorine in your pool. First, you can take simple measures. This includes stopping the supply of chlorine. It also entails shutting off your salt system or opening your pool cover. If that does not work, use sodium thiosulfate pool dechlorinator. As a last resort, you could drain your pool and refill. However, this is truly something that should be reserved for drastic situations. Do everything else we recommend before moving onto draining your pool.