Saltwater System & Chlorine Shock

by Teresa

We just purchased a saltwater system for our pool, but our pool water has turned green. If we go ahead and add the salt and start the saltwater system, will that clear up the green water problem or do I need to shock and re-chlorine the water first?

If I do shock and chlorine the water, can I then go ahead and start using the saltwater system right away?

Thank you!

Thanks for the question Teresa

You won't get rid of the alga problem by turning on the salt water generator (SWG) to 100%. You will need to shock the pool, but this is a process, not an event.

You'll want to turn off the SWG before you shock the pool.

I'd like to have your complete chemical readings:

Chlorine, CYA (cyanuric acid/stabilizer), pH, Alkalinity, Calcium Hardness, and Metals (iron and copper).
It makes troubleshooting much easier and the process of clearing up your pool will go much faster.

Without these numbers I'm just guessing at what the problem is.

You can get this done at your local pool store or get a good test kit. I'd encourage you to get a Taylor FAS-DPD K-2006 pool test kit.

Pool Water Testing

Water Testing Kit

If your CYA (stabilizer) is too high or low and/or the pH is above 8.0ppm, you're going to be playing catch up with the algae for the rest of the Summer.

After you shock the pool and get rid of the algae, you'll need to wait until the chlorine level comes down to an acceptable level to use the SWG again. Around 5 - 6ppm should do it.

The sun and heat will eat up any residual chlorine, but this can take a few days depending on the heat.

Get me the chemical numbers and I'm sure I can help.

One more thing Teresa. Remember that a salt pool is slightly different than a regular chlorine pool. There's lots of good info. on the salt pool and chlorine generator pages:

Salt Water Swimming Pools..System..Maintenance..Chlorine Generator

Chlorine Generator & Salt Cells For Salt Water Swimming Pools

And a huge list of answered question on the Q&A page in the salt pool and chlorine generator categories:

Swimming Pool Questions and Answers

This is my experience with salt pools since 1999 when I had my pool route in Arizona and since 2008 as the pool operator for the YMCA salt pool.

Hope this helps and have a great Summer.


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NEW Salt Water Generator Start Up?

by Lisa
(New Jersey)

I just switched to a salt water generator last summer. I have a DE filter, vinyl liner, built in pool. How do you open the pool now?

I was told you don't put on salt until pool is balanced? I have no idea what the salt generator should be on when I turn it on or anything.

The pool company that put it in I had some issues with so I refuse to call him.. Thank you.

Thanks for the question Lisa

The question says you've had the chlorine generator since last summer. Is that correct? I just want to be sure. Also, is this a new fill or are you opening the pool after it's been winterized. You're in New Jersey so can I assume this is a re-open? A new fill and re-open are different so you'd approach them differently.

I'd like to have your complete chemical readings:

Chlorine, CYA (cyanuric acid/stabilizer), pH, Alkalinity, Calcium Hardness, and Metals (iron and copper) and names of any algaecides you may have used along with clarifiers, phosphate removers, and/or flocs. It makes troubleshooting much easier. You need to know these so you can make the proper adjustments and get on with your pool, not spend hundreds on useless chemicals.

If you're opening the pool for the season you probably have a mess that needs attention. The chemicals are probably out of whack and need to be adjusted.

Now, concerning when to add the salt. You can add the salt at any time you want, but you want to get some chlorine in there as soon as possible. If the CYA is low, below 20ppm, you'll want to use Dichlor chlorine. This is a stabilized form of chlorine.

Once you reach the 30ppm mark, stop with Dichlor and start using your chlorine generator. Keep the generator OFF when adding the Dichlor or shocking the pool.

If the CYA is just right, between 30 - 40ppm you can shock with liquid chlorine. If the CYA is too high, above 70ppm you'll need to do a partial drain and refill to reduce the CYA. There's no chemical to reduce it. The only way is to remove then add fresh water.

Be careful when using Dichlor as it can get out of hand quickly. For every 10ppm of chlorine added with Dichlor, you'll raise the CYA by 9ppm. For every 10ppm of chlorine added with Trichlor tabs you'll raise the CYA by 6ppm.

Adding the salt won't mess with the pH or alkalinity. I drained the Y salt pool once per year and made repairs to the plaster. After a total refill I had it up and running, completely balanced and heated, within 24 hours. And I did this several times.

Just remember to have the filter on and sweep the entire pool very well after adding the salt. Salt is very acidic and you don't want it sitting on the bottom. Add the salt to the deepest part of the pool.

How long to run the salt cell, well, it depends on usage. At the Y I ran the cell 35 - 40% of the time but that was with 5,000 swimmers per month. I doubt you'll have that. Most people run their cells between 5 - 10%. It's really a hit and miss and you'll need to experiment with it.

Here's what you can do. Test the chlorine. Try the cell at 10%, keep filtering for 24 hours, then test the chlorine again. Did it go up? By how much? If the initial reading was 1ppm and after 24 hours it went up to 1.5 or 2.0ppm you might be heading in the right direction. But if the chlorine went from 1ppm to 8ppm, that's way too much and you'll need to dial it down.

It may take a week or two to get the cell right for your particular situation.

If you can get me you're most current chemical readings I can tell you exactly what to do and how to do it. It's also very important to keep the salt within the proper range for your cell. Normally, newer cells have a range between 2700 - 4500ppm salinity. Too low and it won't produce chlorine. Too high and you might burn up the cell or at least shorten it's life.

If you would like personal assistance, I do phone consultations for a donation of your choice. It makes things go much faster and many people have found it extremely beneficial. All your questions will be answered. I have nothing to sell you so you know I'm not bias.

If you choose to not go that route, we can correspond by email but it will slow the process down.

Contact Me


Hope this helps.


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Can't Get The Chlorine Reading Up In Chlorine Generator Pool

by Lynda

I have a new inground pool. 14,700 gallons (exposed aggregate). I have a Pentair IC20 generator. Pool has been opened and running since March 2011. Have not had a problem.

I have my water tested weekly at Pinch a Penny. I add Muriatic Acid about a cup weekly. I had to add maybe 2 - 3 40lb. bags of salt. Water always clear, great pool. Now 2 weeks ago (granted we did have heavy rain and we use our pool daily) My water tested with 0 Free chlorine.

I put my ICG to boost (makes chlorine 100% of time while it is on) 2 days later still 0 chlorine. I was told to add Alkalinity Increaser and 1 gallon shock and algacide and run filter 24 hours then add 2nd gallon shock and stabilizer on the 2nd day. Still getting 0 reading for chlorine.

Pinch a penny says my ICG must not be working. But Pentair tech says if lights are on and all lights are green then it is producing chlorine and I need to shock it. Here are my last readings after the 2nd day of shock

Total Chlorine 0

Free Chlorine O

Combined Chlorine 0

ph 7.8

Acid Demand 2

Total Alkalinity 85

Calcium Hardness 210

Stabilizer 50

TDS 3,600

Salt 2,500

I would greatly appreciate your help am scared to let my children go in pool with a 0 chlorine reading and they are dying to go in. Water looks great and it's hot out.

Please HELP!! Thanks.

Thanks for your question Lynda, and thanks for the readings. It helps tremendously.

The first thing that jumps out at me is the TDS. They're much too high. Anything over 1500 and you'll want to do a partial drain. With a reading of 3600, a full drain is needed.

Next is the salt level. Is this the right range for your salt cell? Normally the bottom range for salt generators is 3000. Are you manually testing the salt level or trusting the cell reading. The cell can give you a false positive. I use and recommend a Myron analog salt meter.

The salt needs to be in range. if it's too low there won't be any chlorine. If it's too high the cell might burn up.

Salt Water Swimming Pools

Chlorine Generator

Have you cleaned the cell? With a TDS level that high the cell might be clogged or calcified up. A 4:1 mixutre of water and muriatic acid will do it. Fill the cell and allow the mixutre to set for 5 minutes, then rinse well with clean water. Use a very soft bristled brush (toothbrush soft) to remove any debris.

Watch the calcium level as well. With a salt cell you'll want to keep it under 250ppm or you run the risk of clogging it up or calcifying it.

The CYA is in the top range. You want to run that between 30 - 50ppm. No more stabilizer.

Check to see if the salt cell is throwing a code. These codes tell you what could be wrong with the cell, if anything. Your owner's manual should have a list of codes, what to look for, and what to do.

If it's a relatively new cell, my guess would be a dirty cell or a low or high salt level. Clean it and check the salt level to be sure it's in range. The YMCA pool's salt range is 3000 - 3500.

I keep it between 3300 - 3500, the mid-to-upper level. This gives me a slight buffer with clogging the cell up. It's best to go a bit higher, but still in range, then allow the level to come down.

For chemicals, all you need right now is liquid chlorine and a PolyQuat 60 algaecide. Shock in the evening, allow for one turnover of the water, then retest in the morning. 1 turnover is normally 8 - 10 hours.

You'll see how the chlorine is holding. Be sure to turn the cell off before shocking. If there's no chlorine reading you'll need to shock it again to get the chlorine in there, then retest in the evening again. Remember to use liquid chlorine.

Hope this helps and have a great Summer.


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Drop Test Sodium Chloride...Salt PPM For A Salt Pool..

What is the correct ppm for a salt water pool of 36,000 gallons?

Thanks for the question

It's not really the gallons of the pool but what your chlorine generator requires that determines the salinity of the pool.

Here are good posts that I would encourage you to read:

Are These Salt Water Pool Balance Readings Right?

Salt Water Pool Maintenance Guide

And also the main salt water pool page and chlorine generator page:

Salt Water Swimming Pools

Chlorine Generator

Most salt cells call for the salinity of the pool to be between 3000 - 4800ppm.

If you're unsure of what your range should be, I would encourage you to contact the manufacturer of your salt cell and ask them.

Get a Myron Salinity Meter and manually test your pool. This will give you a good backup and you can compare your reading against your chlorine generator.

The above links have all the information you need for your salt pool.

And be sure to check out the pool Q&A page. Lots more information there about salt pools, chlorine generators, pool problems, filtration, etc...

Swimming Pool Questions and Answers

Have a fun and safe swimming season.


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