Still salt in water the next year???

[laweatherred]

We have been SLAMing our pool since Saturday 6/2/2018. It was a slimy dark green swamp. It is now a very cloudy blue and we still can’t see the bottom. I know we’re making progress but my question is....IF the pool had salt in it from last year but water level dropped just under half full, and we filled it back up this year, WILL there still be salt in the water?? Should we be SLAMing it as a “SWG” pool?? Our test strip for salt does show it at 2000-2500, which seems right on target! Any and all advice will be greatly appreciated!!!
(I’m not at home to provide any test numbers at the moment, sorry)

 

[JoyfulNoise]

The salt will simply concentrate when the water evaporates. Salinity only decreases when fresh water replaces saline water. Same is true for calcium hardness, it does not get lower unless fresh water displaces pool water.

 

[domct203]

There is no difference in the SLAM between a SWG pool and a manually dosed pool.

 

[laweatherred]

The salt will simply concentrate when the water evaporates. Salinity only decreases when fresh water replaces saline water. Same is true for calcium hardness, it does not get lower unless fresh water displaces pool water.

Ok so if we filled it back up with more than half fresh water it would still NOT be diluted?? Meaning the original salt is still at the same level?

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There is no difference in the SLAM between a SWG pool and a manually dosed pool.

Except with the level of CYA and the FC number are both kept higher with a SWG pool. Correct??

 

[jblizzle]

After you know the water is clean and clear, then the recommended CYA levels are higher for a SWG pool.

But, during the SLAM process, the shock FC level is a function of your current CYA level, not a future target and has nothing to do with whether there is salt in the water.

 

[laweatherred]

I understand this but I was going by the Chlorine/CYA chart on this TPF site. (See photo). If it is a salt water pool the CYA levels run higher which puts the SLAM level as higher. I’m trying to decide if my water STILL has residual salt in it from last year after adding so many fresh gallons this year, then I need to Up my CYA and my Shock FC.

 

[kellyfair]

It doesn’t matter if your water has salt in it. You need to SLAM based on your current CYA.

AFTER the SLAM is over, IF you use a SWG, then you should raise your CYA to recommended level if it isn’t already there, then shoot for the appropriate FC target.

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Look at it this way. Until you actually turn the SWG on, you have a non-SWG pool.

 

[domct203]

I understand this but I was going by the Chlorine/CYA chart on this TPF site. (See photo). If it is a salt water pool the CYA levels run higher which puts the SLAM level as higher. I’m trying to decide if my water STILL has residual salt in it from last year after adding so many fresh gallons this year, then I need to Up my CYA and my Shock FC. View attachment 79744

Both those charts have the exact same SLAM shock level per CYA level. Shock FC level for a SLAM is always 40% of CYA. For a CYA of 60ppm, SLAM shock FC level is 24ppm on both charts.

What am I missing?

 

[Catanzaro]

I find the test strips to be 200-400 ppm off than the reading on the SWG board and Taylor reagents form the salt kit. You mentioned that your "water level dropped half full". Does this mean you lost water from backwashing? If so, your salt levels have definitely dropped. Also, your CYA levels will have dropped as well from backwashing during the SLAM process.

How are you testing your pool levels? With what test kit? Thanks!

 

[laweatherred]

Both those charts have the exact same SLAM shock level per CYA level. Shock FC level for a SLAM is always 40% of CYA. For a CYA of 60ppm, SLAM shock FC level is 24ppm on both charts.

What am I missing?

I’m sorry if I’m confusing everyone. It’s because I’m confused!! Lol. The difference I see is if it has salt, the CYA levels need to be higher than without salt. Currently I’ve had my CYA at 50-60 and SLAMing accordingly. BUT if it DOES have salt it is not recommended to SLAM below 70 CYA. So because the water isn’t clearing up, I’m wondering if I needed to add more stabilizer (up to 70) per the SWG chart??

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I find the test strips to be 200-400 ppm off than the reading on the SWG board and Taylor reagents form the salt kit. You mentioned that your "water level dropped half full". Does this mean you lost water from backwashing? If so, your salt levels have definitely dropped. Also, your CYA levels will have dropped as well from backwashing during the SLAM process.

How are you testing your pool levels? With what test kit? Thanks!

I am using the TF-100 test kit for CYA, FC etc. but only have strips for salt. Our water level dropped over the winter from evaporation. In West Texas where I live we had no rain or snow over the winter. And unfortunately I did not close it properly!!!

 

[jblizzle]

No!

The recommended cya levels for an swg are completely independent from the slam process that you are in now. Forget that you even have an swg until you are done with the slam process.

 

[PoolGate]

For a 10k gallon pool that is already 1/2 empty I think I would have just dumped the rest and started with all clean water.

 

[domct203]

Please re-read the SLAM Process process. It does not say anything about adjusting your CYA, SWG or not. It tells you that the shock level is based on your CYA.

In the Details section it states:

SLAMing an outdoor pool is most effective when CYA is around 30 to 40. Below 30 you lose too much chlorine to sunlight. As CYA goes up, SLAMing requires more and more chlorine, which starts to get impractical around 80 or 90. With CYA above 90 we recommend replacing water to get CYA down before you start the SLAM process.

 

[Pool_Medic]

Your salt level doesn’t affect the cya, the high cya (60-80) is recommended to keep the chlorine gas it produces more stable.
The salt is only needed for the cell to produce chlorine.
The cya is the only reading that matter when determining slam levels.

 

[kellyfair]

I’m sorry if I’m confusing everyone. It’s because I’m confused!! Lol. The difference I see is if it has salt, the CYA levels need to be higher than without salt. Currently I’ve had my CYA at 50-60 and SLAMing accordingly. BUT if it DOES have salt it is not recommended to SLAM below 70 CYA. So because the water isn’t clearing up, I’m wondering if I needed to add more stabilizer (up to 70) per the SWG chart??

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I am using the TF-100 test kit for CYA, FC etc. but only have strips for salt. Our water level dropped over the winter from evaporation. In West Texas where I live we had no rain or snow over the winter. And unfortunately I did not close it properly!!!

No. The “not recommended” that you see on the Chlorine/CYA chart is for normal operation, not SLAM. It is for when SWG is actually being used. Remember my post where I said that until your SWG is turned on, you have a non-saltwater pool?

We are talking two different subjects here. When you SLAM, you raise your FC repeatedly to the SLAM target for your current CYA. Whatever it is. Notice on the chart that the SLAM target is exactly the same for a CYA OF 70, no matter which one you are looking at.

AFTER SLAM, if you plan to use your SWG, you will raise your CYA to one of the recommended values. Since SWGs add chlorine slowly and steadily, the higher CYA protects the small increments better.

If you had so much salt in your pool that all you need is some tequila, but never turned on your SWG, you would have a non-salt pool.

Also, highly recommend the Taylor K-1766 for salt testing.

So, start your SLAM targeting the SLAM FC for whatever your current CYA is. Test FC frequently, raising it to SLAM level if it drops. Brush and vacuum frequently, and if there is debris in the pool, get it out as best you can.

When your water is clear, you will do the overnight chlorine loss test. If you pass it, and your CC is .5 or less, THEN you will raise your CYA to 70 or so, make sure you have enough salt in pool, and turn on SWG.