Need some help with salt + level

[Ralph III]

Hello All,

I need some help with my salt level. I'm using a

Taylor K-1766 salt water test kit and I have a Hayward Aquarite SWG with t15 cell. The SWG states that 3,200ppm is the desired level for the unit and it is currently at 2,800.

These are my test results with the K-1766 test kit....

Wednesday.......4,400ppm
Friday..............3,800ppm
Sunday............3,800ppm

INYOpools has a salt water table and according to it I need to add roughly 100lbs of salt to get to 3,200? Can someone confirm these numbers for me and where do you get your salt? Can you purchase it at Walmart, Dollar General or must you go to a pool store?

Thanks,
Ralph ​

 

[zea3]

If your SWG is reading a lower salt level than the test kit then I would not add more salt. You need to find what the problem is with the SWG and fix it. How old is the SWG? Does it have some white, crusty build up on the plates? If so it may just need to be cleaned.

 

[Brentr]

Like zea3 says. Check your t-15 cell first to see if there is any buildup on the plates and clean if needed. I would add some salt and check the readings on the SWG to see if it came up. I have the K-1766 kit and have never been able to get anywhere close reading to match up to the SWG so I abandoned testing and rely on the readings from the SWG.
I use this salt from Walmart Morton Salt Pool Salt, 40 Lb Bag - Walmart.com
Hopefully others with experience will chime in. Let us know what you find

 

[cfherrman]

What's the water temp?

 

[YippeeSkippy]

I do not trust the reading of a device. I *do* trust the K-1766 Salt Water Tester, although be aware the accepted degree of variance is +/- 400ppm. That isn't usually any issue with chlorine production, IMO.

Is your device making chlorine? If it is... who cares what the device says? A happy device makes chlorine, an un-happy one does not.

If you are unsure if it is, collect a water sample immediately as it comes out of the returns. The FC there should be higher than the rest of the pool if it *is* making chlorine.

Maddie

 

[Ralph III]

Hello All,
The SWG was supposedly replaced recently by the previous home owner and it appears to be working properly. There are no error lights and it states it is "generating" chlorine. I shut the system down for a while so it dropped to 2100 but upon turning it back on it is up to the 2800 and holding steady.

The unit states to use a test kit for accurate measurements so the K-1766 will be what I rely on. I get a reading of 3800 with it? So the question is, do I adjust the SWG percentage to produce more, do I run my pumps longer, or do I add salt. If the later, what is the optimal amount of salt ppm that I should strive for according to the K-1766 kit?

Thanks,
Ralph

 

[YippeeSkippy]

The optimum amount is what the device is set up for. Each brand is a little different. Read the manual if you have one, or check for it online.

Don't add any salt if you don't need to. If you've got chlorine being produced, all is well.

If you want more FC, you can either increase the pump time, or increase the SWG percentage.....or a mixture of both?

Maddie

 

[JamesW]

Does the cell say T-15 on the label?

What are the first four of the serial number on the cell?

What are the diagnostic readings?

 

[Brentr]

So I have to retract my earlier statement on "I have the K-1766 kit and have never been able to get anywhere close reading to match up to the SWG" You got my attention so I decided to test using the K-1766 and here are the results:
SWG - 3600
Temp - 75
All other parameters are within limits.
K-1766 - 4000
Please note a +-of 400ppm is considered within limits.
I know that if my SWG goes below 2800 the low salt light comes on. I usually then bump that reading to 3400 however I added too much salt a few weeks ago and the high salt light has not come on. I know that my SWG is working as I have it adjusted to 15% and my FC is 15. I like my FC on the high side. For me the important thing is knowing how my equipment works and adjusting to suit your needs. Hope this helps

Like zea3 says. Check your t-15 cell first to see if there is any buildup on the plates and clean if needed. I would add some salt and check the readings on the SWG to see if it came up. I have the K-1766 kit and have never been able to get anywhere close reading to match up to the SWG so I abandoned testing and rely on the readings from the SWG.
I use this salt from Walmart Morton Salt Pool Salt, 40 Lb Bag - Walmart.com
Hopefully others with experience will chime in. Let us know what you find

 

[JamesW]

I suspect that the cell is probably old and was not replaced recently.

The serial number has the year that the cell was made.

For example, a serial number starting with 3E13 means:
3 = 3 year warranty.
E = cell
13 = 2013.

 

[Ralph III]

I suspect that the cell is probably old and was not replaced recently.

The serial number has the year that the cell was made.

For example, a serial number starting with 3E13 means:
3 = 3 year warranty.
E = cell
13 = 2013.

1. The serial number on the cell is 3E17. So it was replaced recently as the previous owner stated. It was my impression within the last 6 months or so.

2. I was mistaken about 3200ppm as being "ideal". There is an ideal range as stated from 2700-3200. It is holding at 2800 currently so the SWG shows everything to be good.

3. The numbers listed under the AquaRite diagnostics read as follows....70(?)....23.5(voltage)....23.7(voltage)....4.48(amps)....68p(temp?)....-2800(-?)....AL-2(?)....r 1.55(?)....t-15(cell)....2800(salt). I do not understand a few numbers but everything else seems normal. In addition, there are no error lights displayed.

So why such a discrepancy between the AquaRite and the test kit? Can the AquaRite be calibrated? Also, do I actually have to much salt in the pool given the K-1766 kit says the salt content is 3800ppm? The AquaRite is happy because it thinks/states it to be 2800ppm at the moment?


Thanks,
Ralph​

 

[JamesW]

Is the cell a T-15?

Does it say T-15 on the label?

What is the software revision number?

If the cell is a T-15, I would suspect that the salinity is 2800 and that the K-1766 might be in error.

Are you sure that your test procedure is correct?

 

[Ralph III]

Is the cell a T-15?

Does it say T-15 on the label?

What is the software revision number?

If the cell is a T-15, I would suspect that the salinity is 2800 and that the K-1766 might be in error.

Are you sure that your test procedure is correct?

Yes, it is labeled as a t-15. I don't know what version though so where would I get that? My initial test was high with the k-1766 kit but my last three or four readings have all been exact at 3800. There is no question as to the number of drops it takes or exactly when the sample turns to the milky brown. So I am confident in the testing method having double checked myself several times.

Ralph​

 

[JamesW]

Everything seems to check out ok with the AquaRite. Software version is r1.55.

I'm not sure why the big discrepancy.

The only things left that I can think of are maybe the cell is scaled or the K-1766 is off for some reason.

Check the cell for scaling and clean if there is scale.

Have the salinity tested with an alternate method to double check.

I don't think that it's the thermistor, but check it anyway to see if it's cracked. It's a black, quarter sized disc mounted on the circuit board on the upper right.

 

[JoyfulNoise]

Usually when the cell is reporting lower salinity than the test kit, your cell has scale OR the transition metal coating could be failing prematurely. You can try a quick acid wash of the cell to see if you get any bubbling from calcium scale. The other thing to check is to make sure you are using a 10mL water sample for the salt test. The K-1766 uses a 10mL water sample for 200ppm/drop. A 25mL water sample would give you 80ppm/drop.

 

[Ralph III]

Hello All,

I removed my Hayward T-cell-15 today in order to clean it and this is what I discovered. First, the cell was absolutely pristine inside as if brand new. I went ahead and added the muriatic/water solution but it didn't bubble at all. So very clean.

Anyhow, even after cleaning it continued to give a salinity reading of 2600ppm whereas my Taylor K-1766 kit was giving a reading of 3800, as usual. I then took it to a pool center and they got a reading of 2800ppm.

So apparently my t-cell is perfectly fine and accurate whereas my Taylor test kit is bad? Is there another kit worth considering or should I just have them replace this one?

Thanks,
Ralph​

 

[peirek]

There is no question as to the number of drops it takes or exactly when the sample turns to the milky brown.
Ralph​

Please confirm you are using 10mL sample. It should turn from yellow to a milky salmon (brick) red color. Not milky brown. Are you using a Speedstir? It is a great tool to aid in more accurate measurements for all of your testing.

 

[JoyfulNoise]

If the expiration date on the reagents is still good, then there’s no way the test can be bad unless you are doing the test wrong (adding the wrong drops or using too much pool water). The drops are two different chemicals - the indicator is potassium chromate and the titrant is silver nitrate. Potassium chromate solutions are very stable. Silver nitrate can breakdown from exposure to light but it’s stored in a brown bottle so that’s not usually possible. You can certainly try to mix up your own saltwater solution (table salt and distilled water will be fine) to check your reagents. If you have city water, there’s usually small amount of chloride in the water (typically less than 100ppm) and you could check that. There are no interferences in the salt test as it is only sensitive to chloride (Cl-) ion concentration and nothing else.

If you’re seeing low salt readings than actual at your controller and the test rig at the pool store then that points to the cell as the problem. If the pool store rig was showing normal salt levels then I would say your controller/powersupply was bad. But if your pool water is testing at 3800ppm and the pool store test setup is at the recommended salinity (3600ppm) and both your controller and theirs is saying 2800ppm, then the cell is going bad.

 

[Ralph III]

Hello All,

I will try and answer a few questions.

1) I have performed the test correctly each time and have gotten identical results each time.

*10mm water sample, taken from one foot under water line.
*Add one drop of R-0630 and stir. This is the yellow Chromate which changes the water to yellow. Simple.
*Add one drop of R-0718 and stir after each drop. This is the dark colored Silver Nitrate which changes the color of the water from yellow to brick red. It has taken exactly 19 drops each time on almost a dozen tests I've performed. I also had my wife read and perform the test herself which rendered the exact same results. On the 17th drop it flashes a little brick red then returns fully to yellow. On the 18th drop is flashes a little more brick red then returns fully to yellow. On the 19th drop the water turns fully brick red and stays as such.

Otherwise, I performed the test exactly as described HERE (2:00) and HERE (1:17)

2) I do not understand what you are saying JoyfulNoise? My SWG states my salt level to be around 2600ppm currently. I then had the water tested by a prominent pool store in town and they tested it at 2800ppm. This tells me the SWG is accurate and the Taylor K-1766 kit I have is rendering a bogus number for what ever reason, at 3800ppm.



I have a pool leak at the moment. So I have had to add fresh water to the pool and at times I have had the pump system shut down. So I would expect to get a slightly lower than desired salt content which is exactly what my SWG is showing as well as the pool store. It typically goes back up after an extended run time. I don't think there is anything wrong with the SWG.

Ralph

 

[JoyfulNoise]

Then you are doing the test right and your water has 3800ppm of chloride ion (Cl-) in it.

Your cell is under-reporting the salinity level. Since your cell is the common variable between the pool store test and your own pool (both drive units report 2800ppm salinity when connected to your cell) the cell plates are starting to go bad. When the coating on the plates becomes compromised, or the three electrical connections become compromised, the cell resistance increases and that looks like a lower salinity value.

I bet if you got a replacement cell, your salinity reading would be normal.