Ic40 reading high salt - possible causes?

[Ahultin]

My ic40 has been reading high salt for a while but was producing so i ignored it so long as my taylor k1766 read ok.
A month ago I had a service tech out to warranty replace another microbrite and asked him about it. He tested salt level and came up with 3850 , my taylor was 3900 and the ic40 was 5900. He replaced the flow switch but that resulted in no change. Knowing the warranty is still good till July we made the plan to revisit it in April or may.
Last week the check cell light came on, I pulled the ic40 and it was clean (I have never needed to acid wash it as it's always been clear upon checking). I called the service guy up and he scheduled to come replace the cell

Cell was replaced today with a new in box ic40 but the new cell is reading between 5300 and 5900. My taylor still comes out 3900 , his meter read 3800.

Any thoughts on what could be causing this or shall I continue to blissfully ignore it so long as it is producing?

 

[Jimrahbe]

A,

When the cell is first started, it will go through a calibration cycle where the salt lights flash back and forth between red and green.. I'm sure you have seen this before.. During this calibration, the thermistor in the flow switch tells the cell what the water temperature is, and the cells adjusts the reported salt level based on the water temp.. So, 99.99% of the time the thermistor is bad when the reported salt level is too high or too low.

It is unlikely that two cells with have the same basic issue, so what else is there??

The Cell uses water conductivity to determine the reported salt level... Your TF-Pro Salt test kit does not.. Could there be anything in your pool water that would make is more conductive than normal??

The good news is that the cell will not shut down if it 'thinks' the salt level is high. This means you can run it forever with a reported high salt level, and it will not hurt anything.

If still under warranty, then I'd let Pentair fix it...

Let's see if @JamesW has any ideas on what could cause this issue.

Thanks,

Jim R.

 

[Newdude]

Did the cell use 10 or 25 ml ?

 

[JamesW]

The Cell uses water conductivity to determine the reported salt level

My Taylor still comes out 3900 , his meter read 3800.

The meter also uses conductivity, so it should be the same as the cell.

Maybe get a different drop test and a different meter to see if they agree with anything.

Check the cell temp.

 

[Ahultin]

The meter also uses conductivity, so it should be the same as the cell.

Maybe get a different drop test and a different meter to see if they agree with anything.

Check the cell temp.

Cell water temp (new cell) as shown in the intelliph menu was 97 while the tech was present. We shutoff the solar and rebooted the cell at which point I did not see the water temp reading but the cell then read 5300.
Tech speculated that it could be an issue with the intelliph board so he temporarily bypassed that and nothing changed.

There could be something adding to tds, I know my calcium has been steadily rising and was 625 as of this week. I have a hach 5b kit that as I recall measures tds so maybe I'll give that a go.

 

[JamesW]

We shutoff the solar and rebooted the cell at which point I did not see the water temp reading but the cell then read 5300.

Check to see if the cell temp is accurate.

 

[Ahultin]

Hach5b only reflects hardness as CaCo3 (I'm curious for the chem nerds, i assume this is getting something different than the taylor calcium test as the results where pretty different , 625 on the taylor , 890 on the 5b) not tds so i ordered a tds meter as well as a new salt kit.

Temp looks pretty darn close, 73 on my apera meter from water at the panels 69 reporting on the inteliph

 

[JamesW]

Hach5b only reflects hardness as CaCo3

625 on the Taylor , 890 on the 5b)

1 GPG = 17.118 ppm.

30 GPG = 514 ppm.

Looks like you are outside the range of the test.

The 5 B test Total Hardness, which includes Calcium and Magnesium.

https://www.hach.com/p-dropcount-titration-test-kits/145300

Total hardness is the sum of calcium hardness and magnesium hardness, while calcium hardness is the amount of calcium in water.

The Role of Calcium Hardness in Water Balance
While hardness in water consists of both calcium and magnesium salts ("total hardness"), only the calcium component is relevant in the water balance calculation for pools and spas.

Called the Saturation Index (SI) formula, it considers the interrelationships of four chemical factors—calcium hardness; pH; total alkalinity, as corrected for the contribution of any cyanuric acid stabilizer in use; and, to a much lesser extent, the total dissolved solids level—plus one physical factor, water temperature.

Another common measurement of water hardness is known as total hardness as CaCO3.

This measurement takes into account both Ca2+ and Mg2+ ions.

On average, magnesium hardness represents about 1/3 of total hardness and calcium hardness about 2/3.

If you are comparing your own test results of calcium hardness as CaCO3 with results in publications that use units of total hardness as CaCO3, you can estimate total hardness by multiplying the calcium hardness by 1.5.

If you have a vinyl pool, then it's only important to make sure that the calcium hardness does not go too high, as that could cause scaling. If you have a concrete pool, then you want the calcium to be higher to protect the plaster from deterioration. If your total hardness is high, or if you have a concrete pool, then it would probably be best to get a calcium hardness test kit. If you get your water from a utility, then it should publish a water quality report showing the levels of calcium and magnesium.

Example:
http://montgomerycountymud8.com/operati ... %20CCR.PDF
(Note that total hardness is reported in ppm CaCO₃, while calcium and magnesium are reported in ppm calcium and ppm magnesium. In this example, magnesium contributes about 16 % of the total hardness and calcium contributes about 84 % of the total hardness.)

This is just from your fill water, and the levels will be different based on what chemicals have been added, such as calcium chloride, calcium hypochlorite etc.

You might want to consider upgrading your test kit to one of the recommended ones for better overall test information.

pool-school/pool_test_kit_comparison

 

[JamesW]

625 on the taylor , 890 on the 5b)

890 x 2/3 = 593 ppm.

 

[Ahultin]

Thank you that makes sense so while I was outside of range, assuming a larger margin of error the hach and taylor somewhat agree with each other.

I had bought the hach to test supply water hardness prior to purchasing a replacement whole house softener (which unfortunately does not go to the pool autofill) so it was a "why not" try it on the pool.

I received a fresh k1766 via Amazon (fresh being real loose with a 2/25 best by date ) and repeated the salinity test with that 2x with both times reading 3200 (16 drops). I have a tds meter coming tomorrow so we shall see what that says. I also did a filter clean today and there was quite a bit of fine sediment that came off of them so maybe a ton of stuff in suspension plus the salt plus pushing the calcium is the high tds being read by the ic40?

The ic40 is producing as my fc was 5 yesterday morning and is 9 this evening

As a plan b I got quotes from 2 of the mobile RO trucks today in the event the tds is high and poses an issue which would also give my 2.5yr old water a calcium reset. Both came in at right about $800 so I'll look back at my initial fill water bill and see how that compares.