General Question about Salt and Chlorine Levels

[DaddySquid]

We are new to the saltwater pool crew and our levels are weird to me.

My pool is a circular above ground pool with a diameter of 24' and depth of 4'. We had a rather large rain storm last night and my salt levels are 4000, but the chlorine levels are a little low. If the pool is supposed to generate chlorine from the salt, why is the salt levels elevated, but the chlorine levels low.

Not sure if this makes sense, but trying to learn something new here.

Though, my PH was at 7.9, so had to add some Muriatic Acid. Could this have something to do with it?

Thank you.
Greg

 

[Jimrahbe]

Greg,

The SWCG uses the salt in the pool water to make chlorine, but the salt level does not get consumed or used up by SWCG. After SWCG breaks the salt down to make the chlorine, everything recombines back in the pool, so you still have the same salt level.

Thanks,

Jim R.

 

[PoolStored]

If the pool is supposed to generate chlorine from the salt, why is the salt levels elevated, but the chlorine levels low.

HEY!!! Welcome to TFP!!! Great place to stay a while.

You likely have Chlorine demand (sun, swimmers, organics) causing your chlorine levels to be low. Likely need to turn up your SWCG or run your pump longer. Can you post a full set of test numbers? Particularly your CYA and FC numbers...

Your salt numbers are your salt numbers. May be high, but no relationship to your FC number. How are you testing for your salt level?

A couple good reads:
Pool Care Basics
FC/CYA Levels

We are here to help. For inspiration --> How Clear is TFP Clear?

 

[SoFlo Tech]

Salt levels should not increase with rain. If anything they may slightly decrease if you had over flow which we have quite often during the summer months in FL.
Place your salt cell in 24 hour boost mode to help your chlorine levels return to normal.

 

[DaddySquid]

Good morning,

Our numbers yesterday were:

Free Chlorine = 1 PPM
Combined Chlorine = 2 PPM
PH = 7.9
Alk = 110
Calcium = 70
Cyrn Acid = Not cloudy
Salt = 4000

Right now, we're using test strips to test the salt levels (though, these strips might be old - from previous owner).

 

[PoolStored]

Great, that is helpful.

Questions:

1. So you were able to fill the CYA test tube to the top and the water was still clear?
2. What is your SWCG % set to?
3. Is your pump and SWCG connected together (i.e. run at the same time) and how long do you run your pump.

Based on your measurements, you have a 13,500 gallon pool.

1. I would download pool math --> PoolMath This will help you calculate what to add and when.
2. Without chlorine stabilizer/CYA in your pool, the sun is going to consume Free Chlorine rapidly. I would order/buy enough chlorine stabilizer/CYA to get CYA up to 70. In your case, based on Pool Math, that would be 8 lbs. Don't add it all yet, I would only add enough to get 30ppm into to your pool now, which would be 3 lbs. Put it in a sock and tie it off. Put it in the skimmer or hang in front of a return. After about 30 minutes you can squeeze it a bunch and it will dissolve. I can do 7 lbs in about 30 minutes.
3. I would add 3/4 of a gallon of Liquid Chlorine (3/4 gallon if 10% or 1/2 gallon if 12.5%). This will add 5ppm of FC to your pool and get you up to about 5-6. You always want to follow the recommendations for your FC level based on your CYA level. Here is that chart -->FC/CYA Levels
4. With your CC being that high, I would plan on an Overnight Chlorine Loss Test test tonight. Just follow the instructions, measure FC after sunset and again before sunrise. This will tell us if you have algae/organics.
5. If you do not pass OCLT, then we will help you to SLAM your pool to get rid of algae. Read SLAM process here -->SLAM Process.
6. If you DO pass OCLT, we will help you dial in your SWCG setup to create the FC you need for the pool and make final CYA additions to get you to proper levels.

We got you. For inspiration -->How Clear is TFP Clear?

 

[PoolStored]

Oh, and if you take a moment to fill out your signature, that will really help us help you!

Create Your Signature - Further Reading

www.troublefreepool.com

 

[DaddySquid]

Great, that is helpful.

Questions:

1. So you were able to fill the CYA test tube to the top and the water was still clear?
2. What is your SWCG % set to?
3. Is your pump and SWCG connected together (i.e. run at the same time) and how long do you run your pump.

Based on your measurements, you have a 13,500 gallon pool.

1. I would download pool math --> PoolMath This will help you calculate what to add and when.
2. Without chlorine stabilizer/CYA in your pool, the sun is going to consume Free Chlorine rapidly. I would order/buy enough chlorine stabilizer/CYA to get CYA up to 70. In your case, based on Pool Math, that would be 8 lbs. Don't add it all yet, I would only add enough to get 30ppm into to your pool now, which would be 3 lbs. Put it in a sock and tie it off. Put it in the skimmer or hang in front of a return. After about 30 minutes you can squeeze it a bunch and it will dissolve. I can do 7 lbs in about 30 minutes.
3. I would add 3/4 of a gallon of Liquid Chlorine (3/4 gallon if 10% or 1/2 gallon if 12.5%). This will add 5ppm of FC to your pool and get you up to about 5-6. You always want to follow the recommendations for your FC level based on your CYA level. Here is that chart -->FC/CYA Levels
4. With your CC being that high, I would plan on an Overnight Chlorine Loss Test test tonight. Just follow the instructions, measure FC after sunset and again before sunrise. This will tell us if you have algae/organics.
5. If you do not pass OCLT, then we will help you to SLAM your pool to get rid of algae. Read SLAM process here -->SLAM Process.
6. If you DO pass OCLT, we will help you dial in your SWCG setup to create the FC you need for the pool and make final CYA additions to get you to proper levels.

We got you. For inspiration -->How Clear is TFP Clear?

Good morning,

1. Yes, we filled the CYA test tube to the top and the water was still clear
2. Not sure, will have to figure out how to check that
3. Pump and SWCG are separated. Right now, I am running the pump 24/7

On Saturday, the pool started turning green, so I shocked it over night Saturday and it was a lot better, still a little green and I shocked it again last night. My wife has not checked the chemicals yet (I'm partially color-blind, so can't see the change of colors very well).

 

[PoolStored]

Great, thanks for that.

Then I would just follow steps 1-6 I laid out!

 

[DaddySquid]

Great, thanks for that.

Then I would just follow steps 1-6 I laid out!

Good morning PoolStored,

Quick question for you. For the CYA, when we test our pool, we completely fill the tube (30) right now and can still see the black dot at the bottom, according to step 2 that you outlined above, I need to add stabilizer so that we it eventually becomes cloudy at the 70 mark, which doesn't make sense. We want the CYA test to be cloudy at a lower reading?

 

[DaddySquid]

Good morning PoolStored,

Quick question for you. For the CYA, when we test our pool, we completely fill the tube (30) right now and can still see the black dot at the bottom, according to step 2 that you outlined above, I need to add stabilizer so that we it eventually becomes cloudy at the 70 mark, which doesn't make sense. We want the CYA test to be cloudy at a lower reading?

Good morning PoolStored,

Quick question for you. For the CYA, when we test our pool, we completely fill the tube (30) right now and can still see the black dot at the bottom, according to step 2 that you outlined above, I need to add stabilizer so that we it eventually becomes cloudy at the 70 mark, which doesn't make sense. We want the CYA test to be cloudy at a lower reading?

Also, our FC count is .2 yesterday. We did the OCLT test last night and got .2 last night and .2 this morning.

 

[PoolStored]

Good morning PoolStored,

Quick question for you. For the CYA, when we test our pool, we completely fill the tube (30) right now and can still see the black dot at the bottom, according to step 2 that you outlined above, I need to add stabilizer so that we it eventually becomes cloudy at the 70 mark, which doesn't make sense. We want the CYA test to be cloudy at a lower reading?

So the water is completely clear when you fill the tube? Then use pool math to calculate how much DRY Chlorine Stabilizer (Cyanuric Acid 100%) to add to raise CYA to 30. Put it in a sock (or two), tie it up, put it in the skimmer or hang in front of return. Will dissolve over time. To speed it up, squeeze the sock a bunch, it is kinda fun! You want the dot obscured when you fill to 30. If this still doesn't make sense, ask any questions before you add CYA. Don't want to add too much.

Also, our FC count is .2 yesterday. We did the OCLT test last night and got .2 last night and .2 this morning.

Go back to the instructions for OCLT. You want to have AT LEAST 3ppm FC when you START the OCLT. Overnight Chlorine Loss Test

Given you have had visible algae and have not slammed your pool, I believe you have algae. You can do another OCLT, but I haven't encountered a pool yet, in your situation, that didn't need to SLAM. You can either 1) Get your FC up over 3 and redo OCLT or 2) Start your SLAM.

 

[SJPoe]

I need to add stabilizer so that we it eventually becomes cloudy at the 70 mark, which doesn't make sense. We want the CYA test to be cloudy at a lower reading?

Yes. The CYA test works by the reagent reacting with the CYA in the water, and turning cloudy. The more CYA, the cloudier the water. The cloudier the water, the less water you can see through and still see the dot in the tube. So, if you look at the tube, the numbers start high and get lower as you fill up the tube - the more water you can see through (fuller tube) = less CYA in the water (lower number).

 

[PoolStored]

I need to add stabilizer so that we it eventually becomes cloudy at the 70 mark

To be CRYSTAL Clear...We do not want it to be cloudy at the 70 mark. That would be a CYA of 70. We are shooting for a CYA level of 30ppm. You want the dot to be obscured when you fill to the 30 mark.

 

[DaddySquid]

To be CRYSTAL Clear...We do not want it to be cloudy at the 70 mark. That would be a CYA of 70. We are shooting for a CYA level of 30ppm. You want the dot to be obscured when you fill to the 30 mark.

Ok, so when the dot becomes obscured, that's the CYA reading....so if the dot is clear at 30, that's a bad sign.

 

[PoolStored]

Ok, so when the dot becomes obscured, that's the CYA reading....so if the dot is clear at 30, that's a bad sign.

You got it! Not a "BAD" sign, just means that your CYA is below 30.

Here is some good reading with PICS!!!

CYA Testing - Further Reading

www.troublefreepool.com

 

[DaddySquid]

So, according to PoolMath, I need to add 3 lbs of Dry Stabilizer to get it to 30, but I also have Pool Calculator that says to add 30 oz to get it there. That doesn't make sense to me.

Also, it looks like I need to add 9.6 oz of my dry chlorine to get the FC to 3ppm (I use HTH CAL HYPO 56% - this was left to me from previous owner).

Once I do this and my numbers are registering correctly, I can redo the OCLT. But, you would recommend that I SLAM my pool.

 

[PoolStored]

So, according to PoolMath, I need to add 3 lbs of Dry Stabilizer to get it to 30, but I also have Pool Calculator that says to add 30 oz to get it there. That doesn't make sense to me.

Use PoolMath, it is our tool and matches our recommendations. We KNOW that is right. Ditch Pool Calculator...just sayin. Let's get the CYA going...

Also, it looks like I need to add 9.6 oz of my dry chlorine to get the FC to 3ppm (I use HTH CAL HYPO 56% - this was left to me from previous owner).

You can do that, Cal Hypo adds Calcium but at your levels, won't be an issue. Most of that will be consumed today by the sun, your FC will likely be gone quickly. With 0 CYA in the water the half life of chlorine is 50 minutes. At the end of the day if you go the OCLT route, I would test FC, add the Cal Hypo to get back above 3ppm, wait at least 30 minutes with pump running, then do your start test for the OCLT.

Once I do this and my numbers are registering correctly, I can redo the OCLT. But, you would recommend that I SLAM my pool.

I would recommend slamming. However, we don't slam with Cal Hypo, only liquid chlorine.

 

[DaddySquid]

Use PoolMath, it is our tool and matches our recommendations. We KNOW that is right. Ditch Pool Calculator...just sayin. Let's get the CYA going...

You can do that, Cal Hypo adds Calcium but at your levels, won't be an issue. Most of that will be consumed today by the sun, your FC will likely be gone quickly. With 0 CYA in the water the half life of chlorine is 50 minutes. At the end of the day if you go the OCLT route, I would test FC, add the Cal Hypo to get back above 3ppm, wait at least 30 minutes with pump running, then do your start test for the OCLT.

I would recommend slamming. However, we don't slam with Cal Hypo, only liquid chlorine.

Sorry, that I keep asking dumb questions, I'm new to all this. One more question, can I add the stabilizer and the chlorine to the pool at the same time? Or do you recommend adding the stabilizer first, and once the numbers are upto 30, add the chlorine.

 

[PoolStored]

Sorry, that I keep asking dumb questions, I'm new to all this. One more question, can I add the stabilizer and the chlorine to the pool at the same time? Or do you recommend adding the stabilizer first, and once the numbers are upto 30, add the chlorine.

Yep, load up the stabilizer in the sock and add chlorine away. Are you starting the slam?