# Forum Home Renovation Pools, Spa & Water Features  Saltwater Chlorinator cell quickly blocks up with white stuff. What is the problem?

## berntd

Hello,
My Saltmate cell, which is not self cleaning, goes white, already a few hours after clean it. And within a week, it is solid again. 
That was not always the case and it lasted for months before requiring attention. 
What can be the cause of this? 
I assume it is calcium buildup in the cell.
I had that tested though and the level is perfect according to the pool shop.
The cell was replaced 2017. The griddle like plates still look good. 
Any help will be greatly appreciated.

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## droog

Have you checked the chemical balance of the water ?  https://www.myperfectpool.com.au/sal...up-solved.html 
Edit: Did see that you got it tested but have you tried another shop or a test kit to confirm? Sounds like something is out of balance.

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## berntd

Yes, and  I also test it regularly for chlorine, Ph and total alcalinity. 
I also had it tested for salt, hardness, calcium and stabilizer. 
The total alcalinity is down and so is stabilizer. I will fix that but why is the cell clogging with white stuff?

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## droog

What is your alkalinity reading ? 
From the article I linked  
“The two most important things to minimise calcium buildup or calcium deposits on the salt cell are to: Keep the pool pH levels between 7.4 and 7.6Keep the pool pH levels between 7.4 and 7.6”

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## berntd

> What is your alkalinity reading ? 
> From the article I linked  
> “The two most important things to minimise calcium buildup or calcium deposits on the salt cell are to: Keep the pool pH levels between 7.4 and 7.6Keep the pool pH levels between 7.4 and 7.6”

  Hang on,  you mentioned alcalinity but quote Ph, which is a measure of acidity.
I responded with total alcalinity, which is different.  
My Ph is at the correct levels as mentioned.
It is however difficult to maintain as it constantly wants to rise, requiring acid.

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## droog

Sorry yep got my values confused. 
pH is the most important value so looks like you have that one covered.
Out of suggestions from this end.

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## Whitey66

Are you using a dry chlorine at all?
You need to get your total alkalinity spot on or your pH will bounce all over the place.
Total alkalinity is very important and many people tend to overlook it, make sure it is correct for your pool type.
pH relates to both acid and alkalinity, depending on what the reading is.

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## berntd

Total alcalinity should now be correct as I added 4kg sodium bicarbonate last night. I will re-test tonight. 
I noticed that the the cell is solid again with white stuff and I will have to spend another hour getting it clean.

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## r3nov8or

> Total alcalinity should now be correct as I added 4kg sodium bicarbonate last night. I will re-test tonight....

  4kg sounds like a huge correction. How big is the pool?

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## berntd

The report from the shop wanted 4.8kg. Pool is 55kL

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## Whitey66

You can easily test for total alkalinity yourself, I don't trust the pool places testing and do my own for TA, pH, Chlorine, salt. stabiliser etc.
Have you added any dry granular chlorine?
Do you have a test kit?

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## berntd

Yes I do. But not this time.

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## berntd

I still struggle to understand how any of this would have an effect on the cell clogging up with what appears to be calcium. 
????

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## r3nov8or

> I still struggle to understand how any of this would have an effect on the cell clogging up with what appears to be calcium. 
> ????

   What is your Total Hardness reading? Maybe extremely high?
 Do white flakes end up in your pool? Maybe high Phosphate levels, as described by this guy... https://youtu.be/48Ni5KYdDrQ?t=45

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## berntd

> What is your Total Hardness reading? Maybe extremely high?
>  Do white flakes end up in your pool? Maybe high Phosphate levels, as described by this guy... https://youtu.be/48Ni5KYdDrQ?t=45

  From what I thought, phosphate levels are caused by people swimming and peeing in the water?
I do not have any of that since only one person swims there. I am guessing they are at zero. I think they tested it as well and it was ok.  
I have not noticed any flakes coming from the outlet into the pool.

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## Gooner

This is not a helpful response... but this is the reason why I decided to get rid of my pool.  :Smilie:  I found myself spending more time and money maintaining the thing rather then enjoying it. Pumps had to run most of the time and I often failed to avoid algae growing in the pool come around February time. I then had to go and play chemist with an assortment of chemicals trying to rectify the situation while trying to understand the delicate balance of each reading. I think the local pool shop sometimes led me astray just so that I would come back and buy more chemicals to sort out some other test imbalance or issue. Would usually get it right just in time for the cooler weather.  
Where the pool once was is now a large decked area that gets a whole lot more use and enjoyment.

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## Whitey66

> I still struggle to understand how any of this would have an effect on the cell clogging up with what appears to be calcium. 
> ????

   Well you've asked for help and I've asked you the simple yes or no question twice but you don't seem to want to tell me??  Dry granular chlorine contains "calcium" hypochlorite, I have found that this can cause premature calcium blocking of salt cells despite the calcium levels in the pool checking out ok when tested.  If you have the mesh type electrodes, you will find you get a lot more deposits compared to the solid flat plate type. I have changed over quite a few chlorinators that have had the mesh type electrodes to flat plate types and the electrodes last a lot longer between cleans and produce just as much, if not more chlorine. The warmer the pool water is also affects the level of calcium build up. Phosphates are not only caused by people peeing in your pool - lol, they can be airborne fertiliser landing in your pool or water run off, rotting leaves, dirt, bugs, some pool chemicals, town water, peoples skin etc. phosphates mainly cause issues with algae growth and can affect your chlorines performance. You'll nearly always have phosphates in your pool, it's only when the level gets too high you'll have issues. Why is it taking you an hour to clean the salt cell? This is normally a 10 to 15 minute job.

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## r3nov8or

> From what I thought, phosphate levels are caused by people swimming and peeing in the water?
> I do not have any of that since only one person swims there. I am guessing they are at zero. I think they tested it as well and it was ok.  
> I have not noticed any flakes coming from the outlet into the pool.

  Phosphates can and do hit your pool from all forms of nature. (google says) "The phosphates in your pool come from garden fertilizer runoff, rotting leaves, certain pool chemicals, and your city's water supply. As you swim in your pool, the residue from skin and hair products may also contain phosphates". I would add blown dust and dirt, leaves your pool washes (even if you are pedantic about their removal, the dust remains), bird droppings, dead insects and "any of the crap your neighbours are using on their garden".   
Have you taken a sample of the white gunk to the pool shop? Does it disolve into something that can be tested? What does it taste like? (Does it get you high? You may have struck gold!  :Wink:  ) 
EDIT: nooow I read Whitey's post, but I'd written this  :Smilie:

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## berntd

> Well you've asked for help and I've asked you the simple yes or no question twice but you don't seem to want to tell me?? ... 
> ...Why is it taking you an hour to clean the salt cell? This is normally a 10 to 15 minute job.

  Well, not because I do not want to tell you but because I simply missed it twice.
The screen is tiny, the distractions many etc.... ;-) 
I use liquid chlorine in the blue 15L canisters. 
To unblock that cell is almost a 1h job.
It gets solid like a brick with white stuff.
I then soak it in cell cleaner which is phosforic acid. 
That bubbkes away forever but does not get through the stuff. I then have a brass rod with sn eye bent on the end and I use that to dislodge some chunks from between the plates.
Between acid and pushing stuff out repearedly, an hour is gone. Or at least 40 minutes. Even then. 
How do you clean yours so quickly?

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## berntd

Uhh  

> ....Have you taken a sample of the white gunk to the pool shop? Does it disolve into something that can be tested? What does it taste like? (Does it get you high? You may have struck gold!  )

  I have not taken it to the shop but I told them about it and they performed more tests than normal. It was all good except total alcalinity and stabilizer. 
I DID taste that stuff and it tasted floury. Not soapy, not sour.
It leaves white residue all over the pool gate, bin etc simply by touching with the gloves used, despite rinsing the gloves.
It breaks down in acid by slowly boiling away. 
It is not gold  :Redface: (

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## Whitey66

Get a container that the cell will fit into, you just want to submerge the electrodes not the plastic mounting piece. I find a round bottle the right size and cut the top off it. Fill it with a 9:1 ratio of water and hydrochloric acid (that is 1 part of acid to 9 parts water). remember to add the acid to the water, never add water to the acid. When you lower the cell into the acid-water mix it will bubble a fair bit and may overflow so sit it in a tray or somewhere it won't do damage, and don't forget your eye protection - acid in eyes = not good. You want to maintain the level of solution so it covers the electrodes so you may have to top it up a few times. Then go away and do something else for 10 minutes, no point standing around and watching it unless you have young kids or curious pets around. Take it out and hose it off, if it's not all gone you may need to do it a second time with new solution. I never have to scrape anything off manually doing it this way. If you're not sure what I mean I could probably put up some photos. What type of chlorinator and cell do you have?

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## r3nov8or

I don't understand why you add liquid chlorine to a salt chlorinated pool. For that outcome (more chlorine), I add salt (if needed) and turn up the chlorination rate

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## berntd

> Get a container that the cell will fit into, you just want to submerge the electrodes not the plastic mounting piece. I find a round bottle the right size and cut the top off it. Fill it with a 9:1 ratio of water and hydrochloric acid (that is 1 part of acid to 9 parts water). remember to add the acid to the water, never add water to the acid. When you lower the cell into the acid-water mix it will bubble a fair bit and may overflow so sit it in a tray or somewhere it won't do damage, and don't forget your eye protection - acid in eyes = not good. You want to maintain the level of solution so it covers the electrodes so you may have to top it up a few times. Then go away and do something else for 10 minutes, no point standing around and watching it unless you have young kids or curious pets around. Take it out and hose it off, if it's not all gone you may need to do it a second time with new solution. I never have to scrape anything off manually doing it this way. If you're not sure what I mean I could probably put up some photos. What type of chlorinator and cell do you have?

  I do exactly that. Even with cut bottle.
I sit it all in a bucket.
The acid boils like crazy and mostly ends in the bucket. I refill the bottle etc but it never cleans the cell unless I mechanically intervene as mentioned.
And, I have used undiluted hydrochloric acid too. It is a lot better than the phosforic. But nowhere near 15 minutes. 
Perhaps your cell is not as clogged as mine. The thing is absolutely solid. No plates even visible.

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## berntd

> I don't understand why you add liquid chlorine to a salt chlorinated pool. For that outcome (more chlorine), I add salt (if needed) and turn up the chlorination rate

  How can you not understand that? When the chlorine is low, it needs topping up.
The chlorinator cannot make enough chlorine to compensate when the level becomes low due to rain, algae etc.. It can only maintain a certain level. Even on 12h operation a day, it never makes extra to raise the level.

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## r3nov8or

> How can you not understand that? When the chlorine is low, it needs topping up.
> The chlorinator cannot make enough chlorine to compensate when the level becomes low due to rain, algae etc.. It can only maintain a certain level. Even on 12h operation a day, it never makes extra to raise the level.

  Never ever, not once, have I even considered adding liquid chlorine to my salt chlorinated pool. Just a bag of salt twice a year. I run my chlorinator at Medium or lower all year round. 6 hours per day today in summer, down to 1 hour in deep winter. I didn't specify it - I just thought that's how it is for everyone 
Seems either your salt level, or more likely the capabilities of your salt chlorinator, is not adequate for your pool size . 
Maybe you backwash too much? (wasting chemicals) 
Maybe as Whitey says the liquid chlorine is reacting with the chlorinator. 
Dunno, sorry

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## berntd

> Never ever, not once, have I even considered adding liquid chlorine to my salt chlorinated pool. Just a bag of salt twice a year. I run my chlorinator at Medium or lower all year round. 6 hours per day today in summer, down to 1 hour in deep winter. I didn't specify it - I just thought that's how it is for everyone 
> Seems either your salt level, or more likely the capabilities of your salt chlorinator, is not adequate for your pool size . 
> Maybe you backwash too much? (wasting chemicals) 
> Maybe as Whitey says the liquid chlorine is reacting with the chlorinator. 
> Dunno, sorry

  No, I do not backwash too much. Maybe once a month. I am not a novice at pool keeping. 20 years...
The pool needs 6 bags of salt per year here. The chlorinator runs at 100%, just before the red of the meter scale.
It requires runnjng 10 to 12 hours in summer to keep it up. In winter also an hour.
In summer, it will not make enough chlorine unless the stabilizer is correct. 
The chlorinator is a Saltmate 120. The biggest available (?). I once had it upgraded some years ago to give more amps. It outputs 18A to the cell. 
Everything here has been looked at and serviced or replaced over the years and it is all considered completely normal operation. I have queeried it before. 
Perhaps you have a different type of pool and liner?
This here is a pebble crete inground pool.

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## Whitey66

> I have used undiluted hydrochloric acid too. It is a lot better than the phosforic. But nowhere near 15 minutes.

   You have used straight undiluted acid?? Many of these cells have a coating on them that can be easily damaged if straight hydrochloric acid or metal tools are used to clean them (should only use wood or soft plastic). Some manufacturers don't recommend hydrochloric acid at all, even diluted. The fact that you've used straight hydrochloric acid and a metal tool to clean it I'd say there's a very good chance you've damaged it. I'm not familiar with the Saltmate series but your owners manual should have the details for cleaning the cell. A new plate type salt cell is under $200, if I was you I'd invest in one and before fitting it I'd get the water hardness (calcium content), TA, stabiliser and pH tested and corrected. Get the same pool water tested at several pool shops at the same time and compare the results. It all sounds like a bit of a hassle but when you get it right your life will be a lot better and you'll enjoy your pool a lot more.

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## berntd

> You have used straight undiluted acid?? Many of these cells have a coating on them that can be easily damaged if straight hydrochloric acid or metal tools are used to clean them (should only use wood or soft plastic). Some manufacturers don't recommend hydrochloric acid at all, even diluted. The fact that you've used straight hydrochloric acid and a metal tool to clean it I'd say there's a very good chance you've damaged it. I'm not familiar with the Saltmate series but your owners manual should have the details for cleaning the cell. A new plate type salt cell is under $200, if I was you I'd invest in one and before fitting it I'd get the water hardness (calcium content), TA, stabiliser and pH tested and corrected. Get the same pool water tested at several pool shops at the same time and compare the results. It all sounds like a bit of a hassle but when you get it right your life will be a lot better and you'll enjoy your pool a lot more.

  Yes I have used undiluted acid but not on the current cell. On this one I only used the recommended cell cleaner, which is basically phosphoric acid 30%.
Using undiluted acid in the past did not shorten the life of that cell as far as I could tell. Of course I never jyst left it in there. 
I can't just spend $389, which is what this cell here costs if there is no actual damage to the existing one. 
From my experience, when they are done, the grids fall, to pieces as they erode from the de-plating effect pulling material out of them. I have replaced several over the decades.  
But why is it clogging up with white calcium stuff, is the question.

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## Whitey66

> Yes I have used undiluted acid but not on the current cell. On this one I only used the recommended cell cleaner, which is basically phosphoric acid 30%.
> Using undiluted acid in the past did not shorten the life of that cell as far as I could tell. Of course I never jyst left it in there. 
> I can't just spend $389, which is what this cell here costs if there is no actual damage to the existing one. 
> From my experience, when they are done, the grids fall, to pieces as they erode from the de-plating effect pulling material out of them. I have replaced several over the decades.  
> But why is it clogging up with white calcium stuff, is the question.

  Ok, the cell has a protective layer on the base metal of the electrodes. If you damage this layer by incorrect cleaning it will block up quicker because the protective layer is no longer there. If all your water chemistry is spot on and it's still happening you simply need a new cell. You can buy cheaper plate type cells for around half the price and usually with a better warranty than genuine, I have found these stay a lot cleaner on both my own chlorinator and my clients. I had a mesh type similar to yours and it looked to be in perfect condition and my water chemistry was spot on and I was cleaning it every 2 weeks. I tried a plate type cell from Ebay for $180 and it's been on there for around 4 years and only needs cleaning at about 3 to 6 month intervals, depending on the season. I have had similar results with fitting these cells clients pools after my experience and their cleaning requirements are similar to mine and they are all happy with them. Rather than spending $389 on a genuine cell you would be better off putting that money towards a self cleaning chlorinator that reverses the polarity of the cell automatically, thereby eliminating manual cleaning. But a new aftermarket flat plate cell may be the shot if you chlorinator is still in good nick. This is the cell I've fitted to mine and my clients chlorinators - https://www.ebay.com.au/itm/27183033...ess!2590!AU!-1 
This is the one for your chlorinator from the same company - https://www.ebay.com.au/itm/28176840...ess!2590!AU!-1
There are many other solid plate types out there but I can't vouch for there quality.
Another bonus of the solid plate types is that they are much easier and quicker to clean.

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## berntd

Well, the thing is...
I wanted a plate type cell. They have them. The lady said yep and I was about to get it when the manager came along and casually asked what chlorinator I have.
He then advised that plate cells are for self cleaning chlorinators only as they reverse polarity and I need the grid type. He was adement that the plate type is not suitable. 
And so I don't know.
There must be a reason why they still make the grid type. 
However, I know what you mean with old cells clogging up.
Perhaps there is a non stick coating that wears over time.
I might try and reverse the cell polarity as the other plates should still be fresh because no erosion should takes place on the positive side.

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## Whitey66

I'd say he wanted to sell you the mesh type so he could extract more money from you as there is no way in the world that plate cells are only for self cleaning chlorinators. A lot of pool shop people are very similar to car salesman, you can tell when they're lying because their lips move.  
They don't have a non stick coating on them, have a google for "noble metals" and there is a very good chance your cell will be coated with one or more of them, or oxides of. Titanium is usually used for the cell base metals I think, and palladium, platinum and iridium are often used as a coating. They are metals that are generally used in catalysts, like the catalytic converter in your car. And like the catalytic converter in a car, they should not be cleaned with a brass rod or straight hydrochloric acid.
If it was as simple as reversing the polarity, all pool owners would just swap their connectors over once a week instead of cleaning them. I think you'll also find, that due to the price of coating the plates with these noble metals, that only the anode will be coated. On self cleaning (reverse polarity) cells both anode and cathode are coated. Do yourself a favour and buy a new plate type cell for your chlorinator.

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## berntd

I hear you. If this problem persists, I will do that. Interestingly, adding the 4kg of bicarbonate sodium has made no difference to the Ph. It tested still prefect last night. Unless that stuff has not dissolved yet.
Also, the chlorine level is now sky high due to the stabilizer added. I can decrease the pump operation by 2h or so. 
I did not mean reverse the polarity for cleaning it but to use the un-eroded parts (if they have this coating) for the buildup instead of the already eroded ones. Just to see if the white stuff(!) sticks then or not so much.

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## Whitey66

If your chlorine level is too high,  you won't get accurate pH readings. Get the chlorine down and recheck.

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## berntd

> If your chlorine level is too high,  you won't get accurate pH readings. Get the chlorine down and recheck.

  I have chlorine neutralizer in the test kit.

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## Whitey66

> I have chlorine neutralizer in the test kit.

  Yes, all good test kits have neutralizer in them. If your chlorine is too high you cannot get an accurate pH reading even if you add several drops of neutralizer (you should only use one). Too much chlorine can turn the test water purple and prevent an accurate test. The best way is to get the chlorine and all the other chemistry right, then test the pH.

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## berntd

I now will be testing chlorine daily until it is ok. But the Ph reading would not be that far off, even with it not being 100% accurate at the moment.  I actually expected the 4kg alkalinity stuff to throw the Ph way way high, but it has not.  Should it have?

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## Whitey66

Total alkalinity is not a measure of how acidic or alkaline your pool is, many people get confused by total alkalinity vs pH. Total alkalinity is measured by the amount - ppm (parts per million) in the water, not by how alkaline (pH) the water is.
Have you noticed that when you measure your total alkalinity it is not done on a pH scale?
If your chlorine is way too high you'll be chasing your tail for days or maybe weeks. Turn off the power to your cell until the chlorine is down to about 2.5 to 3 ppm. Check your total alkalinity and correct if necessary, then check your pH and adjust it to 7.4 to 7.6. If you added any acid or soda ash to correct the pH then check the total alkalinity again. Don't add more than about 500mls of acid in one go, do it over a couple of days. Make all changes to water chemistry slowly, don't try to get the quick fix because it can take a while for the added chemicals to fully disperse through the water.

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