Scale coating over the whole pool

[matj6876]

Folks

First post on this forum, apologies if the details, terminology or etiquette are not spot on. No offense is intended!

I have a scale issue, a big one.

History skip this if you are easily bored

My pb completed and filled my pool back in March. When the pool was full I called them to come and do the start up and got no response, for over a week. 9 days after the pool had filled a chap turned up, switched the filter pump on threw some salt and muriatic in the pool along with the cleaner, shook my hand, wished me luck and was gone! Total time on site less than 15 mins. At this point let me state I am a complete newbie at this - never owned a pool before.

My local pool store have been fairly good at getting me started CYA, more acid & pool perfect recommended and added within the week. However they also got me into the nasty habit of "run a test with these strips every week and then bring us in a sample of your pool water once a month - we'll see you straight"

I brushed the plaster twice daily for the first couple of weeks (as directed), then daily for a while and then fell into a pattern of doing it a couple of times a week. On about week four we noticed the plaster "getting lighter in color". We called the pool company and they said not to worry that it was just the plaster curing. Way, way, wrong!

Looking back now, with 20/20 hindsight, it is obvious that was the start of our scale problem. Now some 10 weeks further down the line the black plaster finish is almost white all over and this is why I post...

Two weeks ago I contacted my pool company and complained about the poor start up. After threatening to go through the BBB arbitration process if they did not acknowledge the issue they have agreed to work with me to resolve it.

4 days ago they started lowering the pH of the pool. Over the course of 2 days (using seven gallons of Muriatic Acid) the pH was lowered to <6.2. Almost all the other numbers are off the scale of my test strips too!
FC/ 0
TC/ 0
PH/ <6.2
TA/ 0
CH/ ~250
CYA/ <30
They have asked me to brush twice daily until the scale is gone. It's working but due to the scale of the problem I feel like I will be going until Christmas...2009!

Questions
Before posting these questions I have searched this (and other) forums as best I could. Please point me in the direction of other threads if I have missed something!

:?: My ignorace of pool testing procedures obviously did not help the situation. So I need a decent test kit. I assume all here would recommend the TF100? Need I even look at anything else? Just checking!
:?: I have a Pentair Mastertemp 400 gas heater that has not been bypassed while this low pH process is ongoing is there a danger of damaging it?
:?: Is there a danger of damaging anything else?
:?: How long can I safely continue to have the pool pH this low?
:?: I read with interest the Ascorbic Acid article in the stickies. Will this help with scale?
:?: Once I have finally sorted this problem I believe I need to use a sequestering agent, like Jack's Magic Purple stuff and keep my pool chemistry (particularly pH & alkalinity) in check. Is this correct?
:?: If I use a sequestering agent do people recommend a test kit. It's expensive!

Sorry for all the questions, needed to get them off my back and out there.

Thanks all, in advance appreciation of your comments!

Cheers

 

[JasonLion]

This is a drastic treatment. Not something normally done without a professional paying close attention and the heater bypassed.

Get the TF-100!

Scale is caused by the chemistry getting seriously out of balance. As long as you keep you chemistry in line the scale won't come back/get worse. A sequesterant might well help remove the scale, but you don't need it to prevent future scale.

Running with PH that low poses risks. Low PH can damage the heat exchange coil in the heater. There is probably some scale in the coil as well, but not as much and it won't come off uniformly so there is a definate risk. It is normal to bypass the heater when doing this kind of treatment. There is a much smaller, but not zero, risk to the pump.

Ascorbic acid is too mild to get scale off.

It is impossible to say how long you can keep the PH that low, not all that long and every day is some risk. You want to make sure you bring your PH back up not later than when you get down to your black plaster. You don't want to start taking that off.

 

[Wolfmarsh]

My ignorace of pool testing procedures obviously did not help the situation. So I need a decent test kit. I assume all here would recommend the TF100? Need I even look at anything else? Just checking!

Let me give my opinion on this. I bought the Taylor K-2006, and I wish I had bought the TF100.

Dont get me wrong, the Taylor is a great kit and has a decent price on it.

The TF100 is a little more expensive, but comes with more reagant, and also more tests.

The biggie for me is, you won't find any of the taylor people posting on this board ready to help. What you will find is duraleigh (the maker of the TF100) readily answering questions and avidly helping people here.

You can be certain that once my taylor kit is exhausted, im switching over to the TF100 for sure.

Service and having a presence go a looooonnnggg way in my book. Plus, he is a NC State fan, you cant beat that.

 

[matj6876]

Thanks for your comments. My TF100 is ordered!

A little distressed that if a sequestering agent is not required then my ignorance is what really has caused this. :?

I have the chap from the pool company coming round tomorrow and will get his take again but will most likely stop this. I am too woried about doing more damage.

So that leaves one question. How do I get rid of the scale that's left.... please don't say "drain and acid wash!" - YIKES

 

[JasonLion]

Metal sequesterants can help to both prevent and remove scale deposits. They are most useful for helping to remove scale. Sequesterants are not normally required to prevent scale as you can do that by keeping your PH, TA, and CH levels in the appropriate ranges. The most common cause of scale is high PH. A SWG tends to cause the PH to drift up, so if you are not monitoring the PH it is easy to have the PH get high enough to cause scaling.

There are various ways to remove scale, it depends on how bad it is. Sometimes small reductions in PH and some sequesterant are enough to losen the scale so it can be gotten off with brushing or a pumice stone. Other times you need to go for the full drain and acid wash. In between those two are treatments similar to what you are doing now, except with the heater bypassed. There are specialized products for this which are more effective than acid alone, such as Jack's Magic Stain Solution #2.

There are two risks to the acid procedure. There can be corrosion of metal parts when the PH is below 7.0. Heat exchange coils in heaters are by far the most sensitive to this. Some heaters have titanium coils that are safe even at low PH, but they seem to be rare as they cost extra and not all manufacturers even offer them. Other parts are generally safe for much longer than the heater, but will eventually be affected. The other is the risk to the underlying plaster. Low PH will slowly corrode the plaster once it gets through the scale. Since the scale probably isn't uniform the low PH may affect some areas of plaster before you are able to get all of the scale off. This is usually manegable because it is a fairly slow process. One advantage of a full drain and acid wash is that the amount of acid used in each spot can be controlled to match the amount of scale in that spot.

 

[duraleigh]

Wolf,
Thanks for those kind words. By the way, did you see Uncle Bob this weekend? I heard he and our Dad are getting along much better now. I'M KIDDING, FOLKS, I'M KIDDING! Wolfmarsh and I are only related by the Wolfpack blood that flows thru our veins!! GO STATE!

Matj,

I would really be concerned about running that low pH pool water thru the heater. I would suggest an immediate bypass. If your beatiful blonde kids, relatives, etc. get green hair from swimming, you can almost bet it came from the heater.

There's not a huge amount of info on how to clear up that scaling.....common sense suggests your low pH will be the best way but I really hate to see it that low. I think if you could control it carefully between 6.8 - 7.0 the calcium will dissovle back into the pool water and you'll be fine. I believe a discussion with your PB is in order and express your concerns. If you don't like what you hear from him/her you can take it from there. My impression is he screwed up letting the pH run away (causing the scaling) and now he's overreacting (with the VERY low pH) trying to fix it.

It's not clear to me you'll need a sequestrant. You dont have excess calcium....you have (in the past) excess ph which caused the calcium to precipitate onto the surface of your pool.

Last, If you have any metal surfaces in your pool (Ladder, Hand Rail, etc) that low pH can be corrosive to them. I'm not saying it will, but I think, if it were my pool, I'd be a lot happier if my pH was around that 6.8 - 7.0 range

 

[matj6876]

Thanks again guys

To summarize my understanding of the above, and ask two last questions if you'll indulge me.

It's best to stop this low pH nonsense today, for the sake of my heater, my plaster and my previously fair skinned, blonde haired now red skinned, no haired children!
That is a joke folks, the kids have been nowhere near the pool!

I rebalance the pool and using my newly purchased TF100 keep the pH level on the very low side of Normal (6.8-7.0).
The pool will be usable and because I don't have a huge problem with hardness (CH ~ 250) the stain may eventually dissolve.

If the problem does not go away I bypass the heater and use something along the lines of Jacks Stain solution #2

Apart from being slightly unsightly will the scale itself do any long term damage?
How often should you brush a good (no scale!) plaster finish pool?

 

[JasonLion]

Scale on the pool causes no problems at all except that it can be unsightly and is usually a little rougher than plaster.

You normally brush brand new plaster several times a day for the first couple of week. After than, and assuming no algae or other special problems, you brush only occasionally for cleanliness, once a week or less.

 

[Guest]

First think I noticed is that your CYA is too low for a salt system. If I am not mistaken Pentair recommends a CYA of 75 ppm (SWGs work better when the CYA is toward the maximin range speicified for reasons that are rather lengtly to go into but it will help with the scale problem because it will eventually lead to better pH stability since you can turn the cell output down). Did the PB give you any type of warrenty on the plaster work? If so I would hold them accountable because in a worse case scenerio the only way to get rid of a very badly scaled pool would be to acid wash it.

The reason your pool scaled is because the pH was allowed to rise. pH alone is the one factor that directly effects whether water will be scaling or not. Monitor pH daily and make sure the pH does not climb above 7.8. This is tricky with new plaster and will probably require a lot of acid. Running your pH on the low side and adding a scale treatement (not the same as a seqesterant) might be helpful. Ace Hardware sells such a product under their O-Ace-Sis brands as Calcium Hardness reducers. There are others on the market also. They are NOT HEDP based like the sequesterants like the Purple stuff but are other derivatives of phosphonic acid with other indredients.

 

[duraleigh]

EDIT: Jason and Evan have pretty much covered the issue but I already have this typed up so here's the post :lol:

Yeah, you've got it pretty well summarized. I'm a little above my pay grade when I pontificate on scaling so, hopefully, one of the many smart folks here will help out and correct or confirm what I'm suggesting.

6.8 would be my target pH to help dissove calcium deposits....you can may be go a little lower but I don't have enough experience to confirm that.

Bypassing the heater, if it's easy to do, would be a good idea. If your heat exchanger is copper, the low pH will corrode it into your pool (that's the green hair scenario).

I doubt the scale will have any long term consequences but the sooner you can reverse the process, the better.

Brushing a new plaster pool is quite important and most folks think twice daily is not too much for a couple of weeks. After that, periodic brushing (common sense) is all that's required. In your case, it makes sense to me that brushing the scaled areas can only assist the process and will cause no harm....I'd do it pretty often.

I hope you will continue to post your progress with this issue. Many of us (well, me, at least) need a better understanding of the solution and the info you could provide will be quite valuable. Best of luck.......keep posting.

If you can get slow improvement with the above, you can avoid draining and acid washing which is pretty much a last resort but, nevertheless, a cure.

 

[LadywithIron]

"It's best to stop this low pH nonsense today, for the sake of my heater, my plaster and my previously fair skinned, blonde haired now red skinned, no haired children!"

I hope you have learned your lesson, ALWAYS ALWAYS test the pool water with the mean children in the neighborhood FIRST

 

[matj6876]

@ Jason - Thank you, again! :-D

@ Waterbear - Thanks for the advice. As for the CYA, I probably should have explained better; The numbers in my original post were from about 4 hours after the acid went in. I had previously been running the CYA at between 50 & 100 (again numbers are from test strips so difficult to be accurate). Just for further info I noticed the following happen to my chemistry over the last 5 days of this process:
FC/ dropped from between 1 & 3 to zero (once the CYA was gone and the Texas sunshine kicked in??) but now is up over 10 with the SWG running 24/7
TC/ dropped from between 3 & 5 to zero (once the CYA was gone and the Texas sunshine kicked in??) but now is up over 10 with the SWG running 24/7
PH/ dropped like a stone from over 7.8 (yes, my bad!) to under 6.2 and stayed there
TA/ Dropped from the 120-180 range to 0 and stayed there
CH/ ~250 and has not changed
CYA/ Dropped very quickly from the 50-100 range to <30 (probably 0) and stayed there.
As for a plaster warranty let's just say; discussions are ongoing - they are quoting me $500 for an acid wash and say they will cover half that cost as a "good will gesture".


@ duraleigh - Yep I will continue to post. The pool guys have decided to come back out tomorrow and neutralize (rebalance, I hope) the water and we will reassess. The heater is not easy to bypass and that's one of the reasons we're stopping.
Draining the pool scares me, I have visions of draining the water and the pool just popping up out of the ground.... (15,000 gal of water weighs about 56 tons, right?) ... Tell me I'm being paranoid!

@ LadywithIron - lol, I will remember that next time. :lol:

 

[Guest]

CYA does not go away unless water is rekmoved physically from the pool and replaced with water that does not contain CYA by backwashingk, draining, etc. CYA tests on strips are not very dependable and are influenced by other water quality parameters such as pH, TA, etc. and, to the best of my understanding, require these other parameters to be in normal ranges for valid results on this test.

 

[matj6876]

CYA does not go away unless water is removed physically from the pool and replaced with water that does not contain CYA by backwashingk, draining, etc.

I do remember reading the "CYA does not go away" thing so guess all my numbers above are probably invalid. And my reasoning a complete load of...... :!: Sorry, still learning

CYA tests on strips are not very dependable and are influenced by other water quality parameters such as pH, TA, etc. and, to the best of my understanding, require these other parameters to be in normal ranges for valid results on this test.

Makes sense to me. I would guess that the CYA is still around 50 then. Will find out later this week.... when my TF100 arrives.

 

[matj6876]

Howdy folks

Back from a business trip and my TF100's waiting for me at home - nice. :lol:

It may just turn out to be the best $85 I've ever spent on my pool.

Before ranting too much here's the numbers:
FC/ 12 (SWCG was running 24 hours a day @ 75% for about 7 days - YIKES!!)
CC/ 0.5
TC/ 12.5
PH/ 7.8
TA/ 70
CH/ 650
CYA/ 20
(Temp: 76F)

Lesson 1 - The strips are useless and my local pool shop is not much better.... Test your own water!

Put the numbers in to The Pool Calculator and low and behold....
when checking the CSI number - "Potential to become scaling"
Knowing that often my pH was left to drift up to 8.4 and that my TA used to be about 120... "Scaling Probable"
So the deal here is nothing more than poor pool chemistry causing the issues. I would guess you regulars are not surprised.

Out of curiosity I tested my tap water, which was used to fill the pool. CH of that is 150.
So I asked my pool company how the CH got from 150 to 650. Bear in mind at this stage I have only added salt, acid & stabilizer (+ a bit of pool perfect) to the pool since it was finished.
They reluctantly admitted to me that something (Calcium Chloride) must have been added to bump it that much. On pushing further they said they most likely added too much on start up. Two separate visits from two different people without measuring the levels in between?

So now I have no choice I will be draining the pool next weekend (8/11). Whilst it's empty they have now offered to acid wash it. I will refill it (~$45 for 15000 gal round here) and am hoping that they will pay for the chemicals to start it up.
I'll do this start up hand-in-hand with them, watching what they add!!

Today's questions, with thanks in advance!
:?: I want to use the pool this weekend (8/5) but know I'm going to drain it next weekend (8/11). What chemicals do I have to add to make it safe to swim this weekend.
:?: Any advice on draining the pool?
:?: Any advice on acid washing the pool?
:?: Given the history of this thread any advice on start up?
:?: Reading the threads here and the owner’s manuals for my kit... I am looking at the following for target numbers... comments:
FC/ 2
PH/ 7.4
TA/ 100
CH/ 250
CYA/ 75

Thanks again for all your help folks!
Cheers

 

[JohnT]

Your pool is safe to swim in as is. You probably want to cut back on the SWCG, but the rest of the numbers are well within what I'd consider tolerable for a week.

 

[matj6876]

Thanks folks. A successful weekend!
Nobody turned green, went blind, dissolved or was otherwise harmed by the water. Result! :-D

Was really hoping to get some comments on Acid washing before I get it done....
Some folks at work have told me it will damage my plaster.
Is anyone able to confirm or deny this nasty rumor?

Cheers

 

[duraleigh]

Hi, Matt,

Thanks for the nice comment on the test kit.

Acid washing, by it's nature, has to be done carefully to avoid damage to the plaster or any masonry surface, for that matter.

I think it's one of those things where you have to be comfortable with the folks doing the work. If they're good, your results will be fine. If they're not....................

 

[matj6876]

Well folks it looks like the acid washing worked.
When the pool was drained I had so much scale it was obvious that there would have been no other way of getting it off.
The results are not 100% but I'm back down to a CH of 140 (needs work I know) and most of the scale is gone.

I went from this:

To this:

As I believe it was my PB who screwed up the start up last time I have told him that I will handle it this time.
He was sceptical but does not know about my secret weapon.... this forum! ;o)

This morning after the pool had been filled with tap water my numbers were:
FC/ 0
TC/ 0
PH/ 7.8
TA/ 150
CH/ 140
CYA/ 0

I have so far added:
24oz of 31.45% muriatic acid
3lbs of CYA (in socks in my skimmers)
96oz of 6% bleach (until I can kick in my SWCG)
240lbs Salt

I will test tonight, before adding anything else but I know I should need another 160lbs of salt, another 4lbs CYA and about 15lbs of Calium Chloride.

:?: Do I need to add anything else?
:?: Should I add this stuff in any particular order?
:?: When can I start up my SWCG

Thanks folks! Cheers.

 

[JasonLion]

It sounds like you are doing fine! The only thing to do, in addition to what you already mentioned, is to keep an eye on the PH and FC levels and adjust as needed.

You can get the SWG going as soon as the salt level is right, probably a few hours after you add the remainder of the salt. You probably won't be able to hold an appropriate FC level till the CYA level comes up though. Having the SWG on will help with that, so good to get it going as soon as practical.

Your TA level is a bit high, so the PH will probably start drifting up again as soon as the SWG starts running. Regular acid additions to keep the PH under control will drive the TA down over time. If the rate of PH increase bothers you, you could do the lowering TA procedure (acid to lower PH to 7.0-7.2, aerate, repeat) to bring the TA down to 70-80. But don't try that till after you have the calcium level up.