Cleaning the SWG cell

[PhillipH]

Just closed down my pool. I have a Turbo-Cell-15, and I was planning to take it inside for the winter. Upon removing it, I immediately noticed a really bad buildup on the plates. I assume this is scale formation and/or calcium deposits? Please keep in mind that I just bought this pool in August, and this is my first pool. I'm just getting everything figured out. My pool is plaster. I tested the pool water alot in Aug/Sep as I was learning about pool water chem. Ironically, the Ca Hardness was low when I began. I think it was around 100, and everything I've read says you want to shoot for somewhere around 250ppm for a plaster pool (200-400 being a safe range). So, I did add a good bit of "Balance Pak 300". (I was careful to add it slowly over several weeks while testing in between each application. I would add 3 lbs here, 5 lbs there, etc. Brushed it in at each app. Ended up adding close to 25 lbs I think, over several weeks. Ca Hardness was around 250ppm at my last reading.)

Also, FYI the pH runs high in my pool. It was in the neighborhood of 8.2-ish when I took over maintenance from the weekly pool company service. He was very unconcerned about 8.2. He said the pH is high in a salt water pool and not to be concerned. I tried hard to bring it lower over many weeks using dry acid. I added quite alot of it, but it proved very difficult to budge. I think I got it down to 7.8, but it went back to 8.0. I haven't checked it in awhile.

Sorry for the long post for such a short question, but I like to provide as much detail as possible. Question is, is the buildup just standard scale formation and/or calcium deposits (same thing?), and are there any other "bigger picture" concerns to draw from this bad buildup?

I think I have a good idea of how to clean the cell from other TFP posts and from the Aqua Logic manual.

[attachment=0:2kh351dk]TurboCell.jpg[/attachment:2kh351dk]

Thanks,
Phillip

 

[257WbyMag]

Any pH above 7.8 is harmful in a pool. While it is true that folks with a SWG will have to battle pH rise, that is just an untoward effect of the way the SWG works. You keep it in check with acid additions.

While it is important to keep your pH in check with any pool, it is imperative with a SWG that your pH is not to be allowed to rise above 7.8, lest you end up with a dramatically shortened cell life. Your buildup is probably calcium, but your culprit is likely an unchecked high pH over time.

Muriatic acid is the pH reducer of choice on this forum. It is the easiest to dose accurately and works immediately, all without adding anything extra that you might not want in the pool. Dry acids can add these extra. The one nice thing about the dry acids though is that some folks are a lot more comfortable dealing with it than they are the muriatic acid.

Best for you to check in Pool School and familiarize yourself with pH section. Keep tabs on your pH often until you have it under such a degree of control that it becomes a little more predictable for you.

 

[polyvue]

Now I know exactly what to look for in my cell if the pH goes wrong. Goldine says you should take a stick to it (really!) and if that doesn't work, use an admixture of 1 part muriatic acid and 4 or 5 parts water (acid added to water, not the other way around) and soak it. Regarding what the person from the weekly pool service told you - that a pH of 8.2 was normal for salt water pools.... hmmmh. That may be true for the pools HE maintains! As 257WbyMag stated (who has everything right in my book) SWG pool owners need to stay on top of the pH; I check mine twice a week and add muriatic acid if needed to reduce to 7.3-7.5. And never, never let it go higher than 8.0.

 

[Guest]

Looks like copper sulfite in the water as well by the green coloration. Somebody has either put a copper algaecide in the pool before or has damaged the copper (plumbing, heat exchanger, etc.) with out of whack chemicals

Gotta admit that's the worst one I've ever seen! Try the acid cleaning method previously posted, and good luck!

 

[Strannik]

you obviously haven't seen enough.
i've seen examples where plastic nearly bursts from calcium

here is a very mild one:

 

[JasonLion]

I suspect that your TA level is way too high. If you post a full set of water test results we can tell you how to adjust things so this won't happen again.

By the by, high PH isn't always a problem. But if your TA and/or CH levels are quite high it can be a very serious problem.

 

[taekwondodo]

I was doing a D&F (high CYA, >150ppm) for a customer, and their neighbor stuck up a conversation w/me. Seems she had M/A all over and couldn't figure out why. So I came over and tested her water (not much to do w/pumps running - watch paint dry?).

Her Ca was well over 600ppm, pH ~8.0, no Fc - but she ran a salt system. I asked when the last time she serviced her salt cell... "About a month ago".

I told her we should address the Ca problem, and add some Cl/MA and figure out what was wrong with her salt system. She thanked me and I went back to work next door. About 30 minutes later she comes over with her salt cell and it was 10x worse than your picture (really, no exaggeration). There was so much Ca in it you couldn't see the cell - looked like a bluish white golf-ball was blocking 90% of the input to the cell.

Funny thing is, she insisted on taking care of it herself - and to my knowledge never did anything (I bumped into the husband a month later and he said they hadn't done anything, but if they still have problems next season, they may call me...).

It was a nice pool too...

 

[Guest]

you obviously haven't seen enough.
i've seen examples where plastic nearly bursts from calcium

here is a very mild one:

Is that from your local water?! Or was that just a very neglected pool?

I agree, I have not seen enough if that is a mild example. You should see what I consider "bad" and what I tell folks when I do! That picture just amazes me! Hard to believe that some people can let their things become so neglected.......

 

[PhillipH]

Thanks for all the great advice and info. Keep it coming please!

BTW, when I said I bought the pool in Aug, I should have said that I bought the house/pool in Aug. The pool was put in by the previous owners in 2006. I just took over in Aug. I'm not owning up to an 8.2 pH or a totally calcified salt cell! lol. I may still be learning about pool care, but in general, I work hard to take very good care of my stuff.

If you are bored, you can look back into the Aug/Sep timeframe and see several posts from me regarding my pool chemistry and my test results. That will give you the history. I looked back and copied my last results from 9/12 below. I'll be honest, I ended up temporarily giving up on the pH b/c I had added so much dry acid with no results. The pH just didn't seem to want to budge despite adding way more than was called for on the label (and from the Pool Calc). The pool water was crystal clear throughout Aug/Sep, and I figured I'd just get a fresh start next spring when I reopen.

"Your buildup is probably calcium, but your culprit is likely an unchecked high pH over time."
This makes perfect sense to me. I have read practically every article at TPS, and I will continue to follow the TFP forums and ask questions until I get things under control. I plan to start using muriatic acid next spring. I was just nervous about it when I was getting started in Aug. I actually bought some mur acid today to use in cleaning the salt cell.

Not sure about copper usage in the past, but I'll be using Polyquat 60 from now on per this forum. I used it last month when getting ready to shut down.

FC: 3.6
TC: 3.6
pH: 7.9
CH: 187 (250-300 TH on my test kit)
TA: 120 (consistently 110-130 at the store, 90-110 on my test kit)
CYA: 62 (consistently 55-65 at the store, more like 80-100 on my test kit)

Thanks again,
Phillip

 

[polyvue]

FC: 3.6
TC: 3.6
pH: 7.9
CH: 187 (250-300 TH on my test kit)
TA: 120 (consistently 110-130 at the store, 90-110 on my test kit)
CYA: 62 (consistently 55-65 at the store, more like 80-100 on my test kit)

Though the pool store is apparently providing consistent results (unusual) I would still trust your own testing. It would appear your CH is near top of range, so you don't want to add any calcium. It's typically added via Hardness Increaser (Calcium Chloride) or Cal-Hypo (Calcium Hypochlorite) tabs or shock powder. TA seems to be within normal limits. But the pH is too high and the chlorine is on the low side for your reported CYA level of 80-100.

I ended up temporarily giving up on the pH b/c I had added so much dry acid with no results.

It's not a good idea to use dry acid when you have a SWG. Though I don't recall where this has been discussed my recollection is that it adds sulphur to the pool and is contraindicated for SWG pools per the salt water chlorine generator manufacturers, including Goldline. Stick to muriatic acid.

 

[Strannik]

I agree, I have not seen enough if that is a mild example. You should see what I consider "bad" and what I tell folks when I do! That picture just amazes me! Hard to believe that some people can let their things become so neglected.......

just a neglected pool/customer not cleaning cell when he should

i've seen some where you can't even see plates, it's just a solid block of calcium
not sure if i still have photos

took a lot of acid to clean it

 

[josta]

One time I took my cell to Leslie's for testing, it was quite calcified so he (the store manager) took it out back and poured pure (undiluted) acid into it, and watched it; as soon as it stopped foaming he rinsed it out quickly.

But nowhere have I read to use pure acid...I hope he didn't ruin it. BTW it's been about 6-7 months and is still okay, I guess...

 

[waste]

Hi josta, welcome to TFP!!

While i doubt the cell was severely damaged by the brief exposure to straight acid (31.45%), I've always diluted the acid 10:1 (water: acid) and just repeated the rinse if needed. Of course perhaps he used the 1/2 strength acid that's becoming more common these days.

If you decide to do your own decalcifying in the future, use the 31.45% diluted 10:1

As always, BE SAFE when handling pool chemicals

 

[Strannik]

we use pure (~33%) acid when cleaning cells as well

it's more of a safety concern, handling pure acid is more dangerous hence why customers are advised to dilute it

doesn't do any damage to the cell unless you leave it there for days

 

[PhillipH]

Just FYI, my Aqua Logic manual says to use 2:1 dilution, and the Aqua Rite manual says to use 4:1.

 

[Strannik]

yeah, every manual is different, because it's not a scientifically deducted figure :-D

on the same note, just had a customer call me today saying that his cell has been in for 1.5 years and doesn't get any calcium, asking whether there is anything wrong with cell or the unit. always happy to answer those type of calls

 

[josta]

Thanks for the answers, and the welcome, too!

 

[PhillipH]

Just FYI, but I finally got a chance to clean my cell on Thurs, and the muriatic acid solution cleaned it like a champ. Looks brand new. I used roughly a 2:1 mix and let it sit until it stopped fizzing. Maybe 2-3 hrs. It was spotless.

 

[Budman]

we use pure (~33%) acid when cleaning cells as well

it's more of a safety concern, handling pure acid is more dangerous hence why customers are advised to dilute it

doesn't do any damage to the cell unless you leave it there for days

I know, back to digging up old threads.
Trying to search first and seem to find my answers.
I have a cell that was hard to clean and been working on it for hours. My acid was 14% and i diluted it 50/50.
Wasn't sure if I was doing any damage. According to pentair, they say only 1/2 hour at a time.

 

[Bama Rambler]

If you have 14% acid I'd leave it full strength and clean the cell with it.