Buildup on SWG

ibseanb

Member
Jul 26, 2021
23
Ohio
I found this video that showed holding the UP button until the polarity changes. In my original pic above, the polarity was negative. Ever since I cleaned the cell, it has been positive. I switched the polarity and the status light stayed off and it seems to be producing chlorine. I see bubbles between the plates and some under the cell, and a few by the connector, but not as much as I expected.
 

ibseanb

Member
Jul 26, 2021
23
Ohio
OK, I spoke with C-M-P. The service light comes on after a minute when on positive polarity, but never on negative polarity. He couldn't explain it, and recommended replacing the control unit, and said the cell was most likely fine. The cell will work with their newer systems, but may be difficult to find by itself.
 

jtpipkin

Bronze Supporter
Oct 2, 2016
329
albany, ga
I'd try and find out how to check the cell prior to replacing anything, but I have no clue how. Based on the hours you've used it, there shouldn't be much life left unless they just under rate them
 

jtpipkin

Bronze Supporter
Oct 2, 2016
329
albany, ga
and just a side thought, I had a similar SWG setup when I bought my house. Had other issues with mine and just ended up replacing the whole thing with an aquarite setup myself. Since everything had been previously setup there, it was an easy switch.
 

beegee226

Well-known member
Apr 2, 2018
66
Anaheim/CA
Pool Size
15000
Surface
Plaster
Chlorine
Salt Water Generator
I have the same cell and found my chlorine levels were lower than they used to be. I checked the CYA and sure enough it was low. I added stabilizer, and sure enough the chlorine levels were back to where they should be.
 

ibseanb

Member
Jul 26, 2021
23
Ohio
I ordered a new "CMP PowerClean Salt Ultra 760 Chlorine Generator" for a 60,000 gallon pool. I probably should have done the 520 or whatever, but the 760 was what was already installed; so I just stuck with that. It should be here within the week, so I'm hoping for an easy switch out. Thanks for the help, I'll post back when it's done.
 
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PoolBrews

Well-known member
Oct 16, 2019
346
The Villages, Florida
Side note. That clear cell body is a great idea. You don't need to take it apart to see that it doesn't need--or in your case does need--to be cleaned! Hey Pentair, I have an idea for your next gen IntelliChlor!
Although the idea of a clear cell body sounds great, you are then exposing all of the plates and circuitry to sunlight which will greatly shorten their life. It would be nice to have a clear window with a removable cover on the cell.
 

DanF

Silver Supporter
Mar 17, 2019
412
Chandler, AZ
Pool Size
12500
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
CircuPool RJ-45 Plus
Wondering why the OP had scaling on his cell with such a negative CSI?
 

ibseanb

Member
Jul 26, 2021
23
Ohio
Hey all, good news, mostly. New cell and unit went in without much ado. A TINY drip coming from the housing, like a dropper per 10 minutes. not sure if I should be concerned, it's as tight as I can make it without using a tool. The first attempt I didn't have the notch lined up properly, so there was a sizable leak.

Second, the air pocket that initially showed up as a result of opening the tube went away after running the pump on high for 4 hours. Lots of bubbling came out of the returns and it looked great when I checked on it last night. This afternoon though, half of the tube was air. I kicked it back on high for 4 more hours. Right away the air disappeared and exited through the returns in the pool. I'll double check it in 5 hours.

There is a cleanout just after the SWG. If the air pocket returns, should I open that cleanout, crank up the pump and let it come out there? Just a thought.

The good news is, that for the first time in months, my FC is up to 5 without dumping shock in the pool! The amount of 'bubbles' the SWG puts out when on boost is considerably higher than my previous SWG. It was definitely the culprit.

Oh, and while I was at it, I increased the CH to 280, and got the TA to 180. The PH is down a bit to 7.2. I'm planning on putting more muriatic acid in to drop TA and add some PH up/ aerate to increase PH to 7.4.
 

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ibseanb

Member
Jul 26, 2021
23
Ohio
I just went out to look, and lo and behold, the air pocket was back. I cranked up the pump, it went away. I turned the pump off, then I found the problem. That little drip was enough for it to suck air back into the tube, creating the pocket. I tried flipping the cell around so the tab is up top, but when doing that, the leak was much worse.

The end of the rubber part of the cell sticks out about an 1/8th of an inch or a bit more. It is almost even at the top, but not at the bottom.

The manual says to ensure the rubber O ring goes in, but that is nowhere to be found. maybe a culprit. For now, I have it just right so there is no drip and no pocket that results when turning off the pump.

Back to the original reason for this whole thread. The cell has been installed less than 24 hours, and already there is calcium buildup between the plates. Very small, but visible.

The steps have a return right by, and the steps were littered in calcium deposits. It is possible it was from where I threw a bunch of calcium in to bring up the CH. I hit it with a broom but it didn't dissipate much.

New levels are:

FC 2.6 (pool has been open all day, running at 25% with an air pocket)
TA 180
Ph: 7.2
CH 320
Temp 86

Why the buildup? Thanks!
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
28,492
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
What is your CYA, salt & CSI?

Start by lowering your TA to 60-70.


If you still have scale problems in your SWG some folks have found adding Borates has helped.
 

Oly

Gold Supporter
Jun 28, 2017
2,314
Fresno, CA
Pool Size
27000
Is the air pocket in your cell? If so can your rotate it so the high side is down and air does not trap?
Air in your cell is not ideal for FC production.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
28,492
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
From TA - Further Reading

Why Should TA be Lowered with a SWG?​

Usually a TA on the high end is fine if the pH is stable. However TA does need to be adjusted down with an SWG. The problem is, INSIDE the cell, the CSI is very different than in bulk pool water.

With high TA and aeration from the bubbles the SWG creates, you'll get faster pH rise inside the cell and so there's more potential for scaling. With current reversal, the cell tends to stay clean but you'll get more snowflakes out of the returns. Calcium hardness is only one part of the equation.

If the SWG cell pH rises much above 10 (and it can easily do that) and if there is sufficient levels of carbonate ions available (CO3--), then you will get calcium carbonate precipitation. The higher the TA and pH, the more carbonate anions are available.

Borates are particularly helpful preventing scale in a SWG because the pKa for boric acid / borate anion buffering is approximately 9. That essentially means you get the maximum buffering capacity at a pH of 9 and that tends to hold down the pH rise inside the cell. Keeping the pH below 10 in the SWG cell reduces the risk of calcium and magnesium scaling (insoluble magnesium hydroxide precipitates at a pH of 10.2 or so).
 

ibseanb

Member
Jul 26, 2021
23
Ohio
I called the SWG manufacturer, they did not include an O-Ring, which is probably causing my air bubble/leak. Seems solid now, but man, it's tight. Hoping the O-Ring will help this.

I'll look into borates, and lowering my TA. Lower TA has been a goal, but I couldn't do much when I was continually adding shock that would bring it right back up. Now that the SWG is putting out the good stuff, I can tackle it. I was worried that the model I bought (same was what was already installed) was too powerful (meant for a 60k gallon pool) and even 25% power would be too much chlorine. But overnight it took the FC to about 4ppm (using a test strip).

Overnight the scaling didn't build up much more, but there is quite a bit of white flake near my return.

I appreciate all the help.
 

JimMarshall

Gold Supporter
TFP Guide
Jun 5, 2017
1,090
Oil City PA
I called the SWG manufacturer, they did not include an O-Ring, which is probably causing my air bubble/leak. Seems solid now, but man, it's tight. Hoping the O-Ring will help this.

I'll look into borates, and lowering my TA. Lower TA has been a goal, but I couldn't do much when I was continually adding shock that would bring it right back up. Now that the SWG is putting out the good stuff, I can tackle it. I was worried that the model I bought (same was what was already installed) was too powerful (meant for a 60k gallon pool) and even 25% power would be too much chlorine. But overnight it took the FC to about 4ppm (using a test strip).

Overnight the scaling didn't build up much more, but there is quite a bit of white flake near my return.

I appreciate all the help.

Adding chlorine "shock" does not affect TA
 

ibseanb

Member
Jul 26, 2021
23
Ohio
Well, I'm mostly frustrated from this weekend. While trying to bring down TA, I poured 3 gallons of muriatic acid into the pool, and got it to about 120. PH went down, and, I knew better, but the pool lady told me that PH Up wouldn't bring TA up all that much and to toss some in to bring PH back up to normal levels. Well, in doing that, I still have a PH below 7.2 and a TA of 180. Today is the last warm day for a while, so I'm aerating the pool with the pump on high and jets turned straight up to get as many bubbles as possible. I'd like to have the PH right before we shut the pool for the year.

Second, I should have known better than to trust the guy who owned the pool before me, but I replaced the SWG with the same size as the old one (a CMP 760). It is rated for a 60k gallon pool, mine is 16,500. Even at 25%, the FC was up to 7. Even at its lowest setting, it is producing too much.

I'm going to call the online shop where I bought it, and see if the head units can be switched to a 520, keeping the same cell. If not, I'm going to have to put a 220 timer on the head unit and toggle it on/off every 7 hours or so. My Hayward motor does not turn it on/off, it is always running.

Any thoughts are appreciated.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
28,492
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
PH below 7.2 and a TA of 180. Today is the last warm day for a while, so I'm aerating the pool with the pump on high and jets turned straight up to get as many bubbles as possible. I'd like to have the PH right before we shut the pool for the year.

What do you think the right pH is for shutting the pool?

pH 7.2 is just fine at pool closing. The pH in the closed pool will rise naturally to its equilibrium point.

I think you are doing way too much manipulation of your pH and TA. Any pH in the 7's is ok.
 

ibseanb

Member
Jul 26, 2021
23
Ohio
Thanks. After the muriatic acid, the PH was below 7 (the lowest my test will go), aerating some yesterday and all morning today has brought it up to 7.4.

I don't really want to manipulate the PH at all, but the SWG scaling has been attributed to high TA around the cell; so in trying to deal with that, PH had to suffer.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
28,492
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
Be less heavy handed in the amount of chemicals you add in one dose. Add a dose and test 45 minutes afterwards to see if you reached your desired target. Add a bit more if necessary. You are working way too hard correcting your actions.
 

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