How Do I Bring The Chlorine Level Down In A Salt Water Pool?

by Jill Lummus
(Easily Take Care Of Your Pool)

We have an 18 x 36 , 25K gallon salt water swimming pool.

Our installer didn't explain throughly what or how to bring our chlorine level down if it was too high.

I just did a Free Available Chlorine Test by reaching down 18" or so in the deep end away from the return and dipped the vial full of water.

Then I put 5 drops of Solution #1 in it and swirled it around as instructed it became a bright yellow color, which if I read it correctly means the chlorine level is high?

It say's not to test for pH or alkalinity until you bring the chlorine level down to 1.0 to 3.0 range.

How do I do that? I don't know what to add to my pool to fix it ?

Our Salt Water Chlorine Generator also reads the Chlorine is high.

What do I do and how do I do it?

Today the pool is very clear but has a distinct odor like something is spoiled.

Thanks for the question Jill

I recently answered a similar question about lowering the chlorine level in this post:

Chlorine Is Still Too High

Your style in getting the water is perfect, so good going for that.

You're probably using a yellow OTO test kit.

Being that your familiar with drops, I would encourage you to bump up to a Taylor FAS-DPD K-2006 test kit.

It's the best and will give you the most accurate readings.

Pool Water Testing

Water Testing Kit

I just think other kits leave too much guessing. With a DPD kit you'll know exactly what the readings are.

The above post goes into detail about lowering the chlorine, but here's the gist of it.

1. Allow it to come down naturally

2. Drain 1/3 - 1/2 of the water, refill, and balance the chemicals again

3. Use Thiosulfate. This is a chlorine neutralizer but will mess up the chlorine reading if not done properly.

Only use this in extreme circumstances.

I would recommend taking out any chlorine tabs and turn off the chlorine generator. You don't want any more chlorine in the pool.

Most pool owners will allow the chlorine to come down naturally.

This may take a couple of days up to a week, depending on the current reading and the sun and heat.

You can safely swim in a pool that has a chlorine reading of 5.0ppm - 8.0ppm. Anything higher and you should wait.

I use Thiosulfate when I shock the Y pool (80,000 salt pool).

This is done out of necessity. I can't wait 4 - 5 days until the chlorine comes down naturally.

I get the level down to 8.0ppm, then open the pool back up again.

You can adjust your pH and alkalinity if the chlorine is slightly elevated.

Here are the links for those pages:

Swimming Pool pH Levels

Pool pH

Pool Alkalinity

Total Alkalinity

Being that I don't have your pH or alkalinity readings, I don't know whether they're too high or low. The links above can help with that.

Remember this rule when adjusting your pH and alkalinity:

pH is pump on

Alkalinity is pump off

You can find your post on the Q&A page in the "Chlorine" category if you have other questions or would like to comment on this post.

Swimming Pool Questions and Answers

Hope this helps and have a fun and safe Summer.


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