Intellichlor IC-60 All Lights Green But Not Producing Enough Chlorine.

[Bananimal]

Hi folks, we automated our pool late last swimming season using the Pentair screen logic system. In early spring this year, our FC started to drop and the IC-60 could not keep up. All lights were green, but the system was not producing chlorine. So, I called Pentair as the unit was less than 6 months old. They sent a guy out to replace the unit. Prior to doing so, the tech had mentioned that the only time he sees this is if the TDS are above 4000 PPM. Can anyone corroborate that?

So, after the cell replacement about 1.5 weeks ago, we had to let the pucks I loaded into my trichlor dispenser run out. That happened several days ago. In the interim, I made adjustments to the water balance to get everything in the green in preparation of turning the SWCG back on.

At first, I set the IC-60 to what I used to run it at, 13% for a five hour pump run time. We were losing FC and went from 6.0 to 5.5. Those settings were fine and maintained FC at 6 ppm when we first installed the SWCG. The next day, I cranked the IC-60 up to 40% and the FC fell from 5.5 to 4.0. I then set the IC-60 to 60% and it increased to 4.5 ppm again. Gaining .5 ppm FC. So last night, I set it to 100%. I tested the water when I got home and the FC dropped to 4 ppm. What the heck?

Here's my current readings: (They are well within acceptable levels for the IC-60.)


Pool in-ground 17,600 gal, gunite plaster.

FC 4.0
CC 0.0
Ph 7.5
TA 80
CH 400
CYA 80
Salt 3750
Borates 50
TDS 4,700
Temp 83

I don't get it. We only had a CC reading of .5 ppm once, about a week ago when we were migrating from the failed SWCG to the pucks while getting the Tri-chlor dispenser dialed in.This was the first time in over two years we've had any CC readings at all. So, I immediately dumped a half gallon of chlorine in the pool to boost FC and the readings have been back to 0 ever since.

I started thinking about TDS that was mentioned by the installer tech that came out. So, I took a sample to the pool store today and it came back at 4,700 ppm TDS. Everything else is perfect. Even phosphates. Of course, the girl behind the counter cops an attitude when I question her about salt, CH Up, Borates, CYA, etc. being the cause of the high TDS. She claimed that those chemicals don't show up on the TDS readings and she's never in her career seen reading that high. Ever! Gotta love these people.
Then, the obligatory, "You need to dump your pool water" left her lips. BS, if this were a problem with TDS, everyone running SWCGs would have to dump their pools every spring. I know no one that does this. She then goes off on a spiel that she's had four or five people this year that have had to dump their water. But, get this, due to high nitrates. I asked her, "I don't have that issue do I?" Out came the attitude.

I'm scratching my head here. About the only thing I can think to do is clean out the cartridge filters as maybe organics have built up enough to consume 100% output from an IC-60 in a 17,600 gallon pool? I cant' imagine that, but it's the only other thing I can do. Next would be a call back to Pentair, but they are surely going to blame it on my water. My water has been perfect for just over two years now using the methods from this site. The only problem I have ever had is when the original IC-60 began failing to produce enough FC, and now the replacement too. I am reluctant to believe I need to change a thing.

Any suggestions?

 

[jblizzle]

What does the water look like?
Turn the SWG off, bump the FC up to 10ppm or so, and perform the Overnight Chlorine Loss Test to see if there is something in the water consuming the FC.

 

[Jimrahbe]

B,

I agree with Jason, that you need to run an OCLT... Overnight Chlorine Loss Test

You are not running you SWCG near long enough, or hard enough, to produce the amount of chlorine you need..

Your cell will increase your FC by 14 ppm if running at 100% output and 24/7..

100% for 12 hours is 7 ppm
100% for 6 hours is 3.5 ppm
50% for 6 hours is only 1.75 ppm

Most pools use 2 to 4 ppm per day... and that is without any algae!!!

Thanks for posting,

Jim R.

 

[JamesW]

What does EasyTouch say for the salinity?

Go to diagnostics for the chlorinator and see if it is reporting any errors.

 

[Bananimal]

B,

I agree with Jason, that you need to run an OCLT... Overnight Chlorine Loss Test

You are not running you SWCG near long enough, or hard enough, to produce the amount of chlorine you need..

Your cell will increase your FC by 14 ppm if running at 100% output and 24/7..

100% for 12 hours is 7 ppm
100% for 6 hours is 3.5 ppm
50% for 6 hours is only 1.75 ppm

Most pools use 2 to 4 ppm per day... and that is without any algae!!!

Thanks for posting,

Jim R.

Thanks Jim,

We usually lose 1.5 ppm a day if the pump is off and no one swims. Funny thing is that from early September last year until spring this year, setting the IC-60 to 13% was enough to keep the FC at 6 ppm on a 5 hour run time. Then all of a sudden, the FC started to drop in early spring when water temps rose to about 75 degrees. And yesterday, when I ran the cell at 100% for 5 hours and lost 1 ppm makes no sense when the day before I ran it at 60% and picked up .5 ppm. It's got to be something in the water. OCLT will tell. I'll get that done tonight after cleaning my cartridges.

- - - Updated - - -

What does the water look like?
Turn the SWG off, bump the FC up to 10ppm or so, and perform the Overnight Chlorine Loss Test to see if there is something in the water consuming the FC.

Water looks great and is crystal clear. That's never changed. Will be doing the OCLT tonight.

- - - Updated - - -

What does EasyTouch say for the salinity?

Go to diagnostics for the chlorinator and see if it is reporting any errors.

It's reading 3750 ppm salt levels. No errors on the SWCG. All lights are solid green.

 

[JamesW]

Did you check diagnostics for the chlorinator in Easytouch?

 

[Bananimal]

Did you check diagnostics for the chlorinator in Easytouch?

Just did, thanks. Salt level is 3750 ppm. System OK no errors.

 

[JamesW]

The system is probably OK. If the cell wasn't producing, the system would report an error.

Do a OCLT to eliminate any residual demand then run the FC at 10 to 15 % of CYA for a week.

Forget about TDS. TDS is mostly salt and really doesn't mean anything. The number being reported is probably not accurate.

Your system does a TDS test when it tests for salinity. It's just a conductivity test that is correlated to a specific amount of dissolved solids depending on the assumed makeup of the TDS. For your system, the assumed makeup is mostly salt with some calcium, cyanuric acid, borate, magnesium etc.

I recommend the K-1766 salt test kit.

K-1766 Taylor Salt Test

If the pool store is using something like a Myron L Pool Meter set to TDS, then they’re using it incorrectly. The TDS setting assumes a dissolved solids makeup of 40% sodium sulfate, 40% sodium bicarbonate, and 20% sodium chloride, which is not accurate for a pool where the dissolved solids makeup is known to be almost entirely sodium chloride.

The 442 Standard Solutions consist of the following salt ratios: 40% sodium sulfate, 40% sodium bicarbonate, and 20% sodium chloride. This salt ratio has conductivity characteristics closely matching natural waters.

PoolMeter™

As you can see in the chart below, the ppm of dissolved solids is different depending on the assumed makeup of the constituent components of the TDS. It shows that the TDS assuming a 442 makeup is higher than the TDS assuming a sodium chloride makeup at the same conductivity.

A K-1766 test is specific to chloride and can be compared to the box reading to verify that the TDS is mostly sodium chloride.

The pool store probably set the meter to salinity, took a reading, and then switched to TDS and took another reading, which is not a valid test.

What salinity reading did the pool store tell you?

4,700 ppm TDS (442) correlates to about 3,100 ppm sodium chloride.

 

[Bananimal]

Thanks Jim, that is fantastic information.

I was surprised that the pool store readings were so far off of my own readings. They are as follows:

FC 3
TC 3
Salt 3,500
CH 320
CYA 60
TA 100
pH 7.6
Copper 0
Iron 0
Phosphates 0
TDS 4700

 

[JamesW]

How are you measuring salt?

 

[domct203]

Thanks Jim, that is fantastic information.

I was surprised that the pool store readings were so far off of my own readings. They are as follows:

FC 3
TC 3
Salt 3,500
CH 320
CYA 60
TA 100
pH 7.6
Copper 0
Iron 0
Phosphates 0
TDS 4700

Are those the pool store results?

 

[Bananimal]

How are you measuring salt?

I'm using the readings from Screen Logic.

- - - Updated - - -

Are those the pool store results?

Yes.

Here's my results as tested just before bringing my water to the pool store.

FC 4.0
CC 0.0
Ph 7.5
TA 80
CH 400
CYA 80
Salt 3750
Borates 50
Temp 83

 

[Bananimal]

I've cleaned the filtration system out completely. FC was at 6.5 this afternoon, but we put in a quart of liquid chlorine last night. I just added another 64 oz. of liquid chlorine to boost FC to just above 10. We'll be testing levels again after sunset and see what we lose overnight.

- - - Updated - - -

B,

I agree with Jason, that you need to run an OCLT... Overnight Chlorine Loss Test

You are not running you SWCG near long enough, or hard enough, to produce the amount of chlorine you need..

Your cell will increase your FC by 14 ppm if running at 100% output and 24/7..

100% for 12 hours is 7 ppm
100% for 6 hours is 3.5 ppm
50% for 6 hours is only 1.75 ppm

Most pools use 2 to 4 ppm per day... and that is without any algae!!!

Thanks for posting,

Jim R.

Once we determine there's no residual loss over night, I'm going to set it for a 6 hour run at 100% and see what we get. The 13% I set it at where it was working like that for 6 months led me to believe that 13% on a 5 hour pump run keeps FC levels steady for my pool. Which it did.

 

[JamesW]

Ok, forget about the tds readings. They are completely bogus.

I would still recommend that you get a k-1766 test kit to track salinity independently of the box.

 

[Bananimal]

Ok, forget about the tds readings. They are completely bogus.

I would still recommend that you get a k-1766 test kit to track salinity independently of the box.

Thanks. Ordered!

 

[Bananimal]

So, the FC last night was 10. This morning just before sunrise, it was 10. No loss whatsoever. I set the IC60 for a 50% run at 6 hours and the FC reading this evening is 10 ppm. No change there. I guess it is working? I just don't understand why I was able to set it to 13% on a 6 hour run time from October 2017 through April 2018 and it held FC steady the entire time.

 

[JamesW]

October to April is winter and daily fc usage drops way down. Completely normal.

 

[jblizzle]

I think the answers is ... from Oct to Apr the water was cooler and the sun was less intense.
Also, as SWG age to do start to put out less chlorine when running.

 

[Bananimal]

Alright gents, I suppose that wraps this up. Thanks to each of you for taking the time to assist. It's greatly appreciated.

 

[Bananimal]

Well, I'm back with the same problem here. I have no idea what the heck is going on. This is super frustrating. Last night we went to bed and the FC was at 11.5 ppm. CCs were at 0 as they have been since my last post here. CC was at 0 again this morning and FC was 11.5. So, I set the IC60 for a 100% run for 9 hours today. Get home from work and I lost .5 ppm chlorine. My pool is 1/3 the rated size of the IC60 and it cannot generate enough chlorine. A $700 SWCG that cannot keep up on a less than 20k gallon pool. I'm at my wits end on this. No one knows what the heck is going on. Not the pool store, not Pentair and not the guy that came out and replaced the unit three- four weeks ago. As I said earlier, when we first installed the IC60, running it 6 hours a day at 13-17% allowed it to keep up. that was from early October last year (we swim until late Novemeber) until April this year. No problems what so ever. Then all of a sudden, when the water temps rose above 75 degrees in April, it stopped producing sufficient FC. Had it replaced and the same thing. Any ideas? Anyone? Perhaps a Easy Touch control unit issue?