Pentair IC40 cell -- no longer working...

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Re: Question for experts: Can borates affect salt level read

JasonLion said:
No, adding borates has no effect on salt levels.

Or more technically, it raises the salt level just a tiny bit, but so little that we don't even think about it.

Rapidly falling salt levels are almost invariably a leak being masked by an auto fill system, which causes rapid water replacement.
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Thanks for the quick response, Jason.

I'm 98 percent certain that my pool does not have a significant leak because my autofill has been shut off for the last month or so. About the end of last year, I raised the water level in my pool after doing a partial drain and fill. I was hoping that the fresh water might soften up some of the waterline scale that developed last year. In order to maintain the higher level, I adjusted the float switch in the autofill. When I "opened" the pool around the middle/end of last month, I shut off the autofill so that the water levels could return to normal.

Just a few days ago, I readjusted the float switch to maintain a normal waterline. I then turned the autofill valve back on. In the last month or so, my water level dropped by about 1-2 inches max. This is what I would expect with normal evaporation rates and splashout.

If anything, I would have expected the salt levels to rise slightly as the temperatures rose by a few degrees and the total volume of water decreased by maybe 2-3 percent.

Anyhow, I'm going to take a water sample and have it tested at a couple of different pool stores tomorrow.
 
peterl1365 said:
I posted this question in the Chemistry 201 section:

Topics merged. Please keep everything relating to one problem or project together in once place. Thanks JasonLion
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Sorry for cross-posting. I thought it might be appropriate to post in the Chemistry section because it concerned borates.
 
Also, the reason I posted in Chemistry 201 wast that I wanted to ask the more specific question as to whether borates could cause inaccurate salt level readings.

As I understand the chemistry, the NaCl levels are not affected. However, could the borates alter the conductivity of the water in such a way that the method Pentair uses to calculate salt levels would return inaccurate results.

According to thepoolman's post on April 24th, the IC40 calculates salt levels as a function of temperature and conductivity across the cell plates. If the conductivity of the water was decreased as a result of adding borates, then the salt readings would also decrease and report values much lower than the true NaCl levels.

If I recall, the relation between salinity and conductivity is not linear. So could a small decrease in conductivity result in a large change in *indicated* salt levels?
 
thepoolman said:
If the pool store reads 3200, the service man reads 1800, and your autofill is off, someone hasn't calibrated their meter correctly or was not set correctly.
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Well, that's what I hope to find out tomorrow by getting tests done at multiple locations. I'm guessing most pool stores use a typical pocket-tester device. I don't know what type of sensor the service guy used. Does Pentair make and/or sell a salt level meter?

BTW, for the record, the service guy was not a Pentair employee. Just a pool service/repair company contracted by Pentair to handle field issues.
 
I had my pool water tested at a Leslie's store near my work. This is a different store than my test from a few weeks ago.

The result: 2700 ppm measured using a salt test strip. Their pocket tester was not working.

Not as high as I was thinking, but much higher than the 1800 ppm measured by the pool guy.

I'm going to try and find a non-Leslies store around here to test the remainder of the water.
 
Well, this is getting interesting. Went to two other pool stores and had my water tested using a pocket tester. Both stores measured the salt levels at approx 1800-1900 ppm.

So, I'm faced with two possibilities:

1. Something about the borates affects the conductivity of the water which is causing the salt testers to return inaccurate results
2. I do in fact have a pool leak.

I shut off my autofill again Thursday evening. 24 hours later, the water level does appear to have dropped by a little, maybe a half inch or so. This might be normal, though, as it was a hot windy day yesterday. Southern California had a moderate Santa Ana condition on Thursday and Friday which is characterized by hot, very dry winds coming from the inland deserts. On days like this, it would probably be expected to experience higher than normal evaporation losses. Unfortunately, I don't have a baseline rate to compare it to.

This morning, I initiated a bucket test to see if there truly is a leak.
 
The best thing I did was purchase the TF 100 test kit and the salt test kit last year,all of that running around is a pain,I also purchased the speedstir which makes it much easier ,now I compare the SWG reading and my salt test and know that if they are both close the readings are good. If you can do this you won't be sorry.
 
heidiho said:
The best thing I did was purchase the TF 100 test kit and the salt test kit last year,all of that running around is a pain,I also purchased the speedstir which makes it much easier ,now I compare the SWG reading and my salt test and know that if they are both close the readings are good. If you can do this you won't be sorry.
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I may have to try that. However, the immediate problem is more mysterious. The running around was a one-time thing, and it did somewhat validate the readings from the cell and from the Pentair guy's pocket tester.

My bucket test was generally negative after approximately 30 hrs. I can't discern any significant difference between the bucket level and the pool level. In fact, there doesn't appear to be any significant drop in water level in the last ~48 hrs. Maybe a quarter-inch at most, which is to be expected due to evaporation. The last couple of days have been relatively mild, with daytime highs around 80 degrees and partly cloudy skies. Don't know what the RH was, but it wasn't unusually dry or humid. Kind of typical for early May around here.

This does tend to confirm my observation that there's only been about a 2-3 inch drop in water level since early-April when I turned off the auto-fill to reduce my water level. FWIW, I looked up the Pan Evaporation Rate data for Southern California. Averaged across the L.A. and S.D. areas, this historical average is around 6 inches per month for the months of April/May.

I'm stumped, so I'll just try adding a couple bags of salt to see if I can at least get the salt level to an acceptable level. My concern is if I add enough salt to get the IC40 running, I might be at a true salt level of 5000 ppm or more. The IC40 won't know it, but could any damage occur?
 
Update:

Well, I've pretty much confirmed that I do not have a leak. I've had the autofill off since 6pm on May 3rd. As of noon today, May 11, the water level has not dropped significantly. Maybe about an inch or so over 7.5 days. Hard to tell because we had an unusual rainshower about 5 days ago that added roughly 1/3 to 1/2 inch to the pool level. So overall, the level is about 1/2 inch below the level on May 3rd.

So today I added 3 bags of salt. The indicated salt level rose from 1650 ppm to 2650 ppm. The "Low Salt" LED is still red, but the IC40 is reporting status as "OK" despite the low salt level. I've currently set it to superchlorinate mode for 12 hours, and I can see the normal chlorine gas bubbles coming out the pool returns.

I'm pretty certain that the "real" salt level is closer to 4000-4500 ppm, but I guess I can live with the current situation. Hopefully, the cell continues to operate without any further issues.
 

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If I had to guess, your salt level is close to what your system and pool stores are telling you. Can't explain your loss of salt if no leak, but everything you're saying makes me think you just need to add a few more bags of salt.

If you don't have a pool store with a Myron conductivity tester, buy one for yourself (along with some calibration solution) and you'll have instant test results to compare to your easytouch.
 
thepoolman said:
If I had to guess, your salt level is close to what your system and pool stores are telling you. Can't explain your loss of salt if no leak, but everything you're saying makes me think you just need to add a few more bags of salt.

If you don't have a pool store with a Myron conductivity tester, buy one for yourself (along with some calibration solution) and you'll have instant test results to compare to your easytouch.
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Thanks Poolman, I understand what you're saying, but there is no rational reason for the salt levels to drop if there was no leak. I'm certainly willing to listen to any theories. I would be happy to add a couple more bags, but I'm concerned that the water might become too saline and start corroding my pool surfaces and equipment. What is the salinity level at which I need to be concerned about stuff like that?

As a point of reference, when the pool was brand new, I added 10 bags of salt to fresh water. The resulting salt level at the time was 3200-3500 ppm, and it remained basically constant for the next 2 years until the salt cell failed for unknown reasons.

In the last month, I've added 10 bags of salt to partially salty water (tested at the pool store to be approx 800 ppm as of March 15th). Yet, the measured salt level is only 2650 ppm.

I'll look for a Myron conductivity tester, but I suspect that it is just a more accurate and precise version of the pocket testers. At my last job, I actually had access to a high-end conductivity/resistivity tester. Unfortunately, I don't have anything like that now.

I think I'll look into the drop-based tests.
 
waters'edge said:
Wondering if you have resolved this issue. I'm dealing with essentially the same problem.
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Not sure if resolved is the right word. I've got a functioning SWG. I'm just concerened that the true salt levels are significantly higher that what the various meters are indicating.

For now, I don't know if there is a better solution. Even if I got a more "accurate" reading, it wouldn't help because the only reading that really matters is the sensor in the IC40.
 
I finally traced it back to operator error - I had increased the run time percentage using the Easy Touch and for some reason the swg responded by not producing chlorine, although all the LEDs on the control panel were green. I check the salt level on the remotes' readout every three days and was surprised it had dropped by 1000ppm. I'm assuming it had something to do with the cell not generating. After cleaning and rebooting, salt levels were back up and the thing is running normally :roll: I half expect the thing to quit completely as it's past the average life span of most cells.

Didn't remember that the salt level went down after adding borates, but when I read your post I did go back through my testing spreadsheet to rule it out. Btw, I have not been on the beneficial end of things with borates. Unlike many, my pH still rises .1/day so I add MA every three days. Water's beautiful though.
 
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