Is this scale?

Slm3rob

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Bronze Supporter
Mar 16, 2016
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Conroe, TX
Can someone tell me if this is scale? Pool is 10 months old. Luna Quartz finish. Since fill, the pool has used 1/2 to 1 gallon of acid a week. Except in the winter when we had a solar cover on part of the time. Didn't use as much then. CH has risen since fill even though we have had quite a bit of rain over the past few months which has diluted CYA but not the CH. I can't figure that out.

i also have lots of little white drips coming down the side of the pool, especially on the side the sun doesn't directly hit. I scrape them off and they come back. There were a lot more in it today then last week... CH is 475 today. Full numbers below

If is is scale, it covers most of the pool floor and is creeping up the sides.

IMG_1137.jpgIMG_1140.jpg

FC: 11
CC: .5
PH: 7.6
TA: 90
CH: 475
CYA: 65

added CYA today to bring it up and the chlorine is a little Higher than usual because I added a little extra bleach yesterday as we eve going to have a group of little kids over but that didn't happen. It's usually is between 7-8.

Thanks!
Linda
 
Those numbers don't indicate scale but if your pH spends a fair amount of time at 7.8 and higher then it could be scale. Is it rough and raised? Use PoolMath to calculate your CSI. Keep it between -0.3 and 0 to prevent scale. Move it down to -0.8 to -0.9 and brush a lot to dissolve the scale.

More here, Pool School - Calcium Scaling
 
The PH has been difficult to keep below 7.8. I'll get it to 7.5 and in 3 days it's over 8. This has been a constant since the pool was built. I've been working on lowering the TA.

It's not really rough and raised and although you can't really tell in the pictures, it covers almost all of the bottom of the pool and appears to be creeping up the sides. For the most part I've tried to pay attention to the csi but I know it has been over 0 though not over the .6 limit. Right now according to pool math it is .1 with the numbers I've posted.

I thought it was the plaster continuing to cure, but when I started seeing the little white drips in the pool I started to question it. I've read through pool school on scaling and the long post about calcium deposits. I'll re read to make sure I didn't miss anything. It just doesn't look as pretty like it did last fall.

i guess I need to know if I just need to micromanage it to get rid of it if it is scale.
 
I got in the pool today and really paid attention to the surface. It's definitely rougher on the bottom of the pool where what appears to be scale is. The sides are smoother.

Can I manage the PH in such a way to get rid of it? Or are there any tricks that don't involve draining?

i can't figure out how it happened... have really tried to manage the PH since the pool was built.
 
Concerning the "drips," if they are raised above the surface, rough, and white, and you are able to scrape them off, but then they return in time, it may be that they are known as "calcium nodules." If so, then the plaster is losing its' bonding. Contact your contractor. Posting a picture of a white nodule would help us diagnose.

However, the pictures above indicate that the dark plaster color is losing the color and turning white and in a spotting or streaky pattern.
If so, review this thread: White Spotting of New Plaster Pools
That indicates a different problem and is not calcium nodules, nor is it calcium scaling. It may be that the white drip lines are simply discolorations due to improper plastering techniques that appear after a few months.
 
Concerning the "drips," if they are raised above the surface, rough, and white, and you are able to scrape them off, but then they return in time, it may be that they are known as "calcium nodules." If so, then the plaster is losing its' bonding. Contact your contractor. Posting a picture of a white nodule would help us diagnose.

However, the pictures above indicate that the dark plaster color is losing the color and turning white and in a spotting or streaky pattern.
If so, review this thread: White Spotting of New Plaster Pools
That indicates a different problem and is not calcium nodules, nor is it calcium scaling. It may be that the white drip lines are simply discolorations due to improper plastering techniques that appear after a few months.


Attaching a few more ore pics of both issues. The spotting in the above thread is very similar (especially the second pic) to what I'm seeing. I tried to use a pumice stone to rub some of it off (thinking if it was scale it would come off) but didn't see any difference. I couldn't get these pics in the right order...there are two with nodules and two with the spotting...

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It appears that your pool plaster finish has both problems; calcium nodules and massive white spotting, or what some plasterers incorrectly suggest that it is "spot etching".
So yes, calcium nodules can be scraped off, but the white spotting on colored plaster will not come off.
Both problems are a defect in the workmanship, so I suggest you call the plastering contractor and suggest that a re-plaster is in order.
 
Onbalance,

Thank you so much. I read the links you sent me and it lines up with what I'm experiencing. My calcium levels have risen from 300-325 about a month after the pool was built when I began to take care of the pool to 500 plus now.

No reason that I can come up with, s my fill water has a CH of 100. It's been bothering me for a about 3 months as to why the calcium keeps rising. It just didn't make sense to me since we have had a good amount of rain and my CYA has decreased due to rain. The ph wants to rise but I've tried to keep a close watch on it and lower it to 7.5 whenever it rises to 8 or more (about every 3-4 days).

The TA has been almost impossible to lower. I had it lowered in the fall and kept a watch on it then about March or so it shot up and I've struggled to get it down below 110 - attempting to get the PH to stabilize.

Scale didn't make sense to me, but I just thought, I'm new to taking care of the chemicals and maybe I've messed something up. I've kept records of my testing.

Thank you so much for your help.

I am curious as to what you found happened to the samples of plaster you were experimenting with in 2012- 2013. You and Chemgeek were discussing it. If you have a link to your results I'd be interested in reading it.
 
has nothing to do with the plaster don't waste your time fighting a never ending battle. looks to me like scale built up over time, I can assure you that its all on the surface of the plaster, a good drain and acid wash will take care of the problem. no need for a replaster on a 10 month old quartz finish lol. your CH is high but draining will reset that clock :) & yes its a constant battle with the PH on a quartz finish I recommend 7.2
 
has nothing to do with the plaster don't waste your time fighting a never ending battle. looks to me like scale built up over time, I can assure you that its all on the surface of the plaster, a good drain and acid wash will take care of the problem. no need for a replaster on a 10 month old quartz finish lol. your CH is high but draining will reset that clock :) & yes its a constant battle with the PH on a quartz finish I recommend 7.2

Gilbert, thanks. The plaster company is coming out to take a look at it. The entire finish except for the middle of the pool in the bottom doesn't look great. I just want it to look like it did a few months ago. The calcium nodules keep popping up... more every few days, which concerns me. There are probably 40 or so of them throughout the pool. Maybe more ...

When I try to get the PH to 7.2 it will stay there for one day and go to 7.5. It will not stay at 7.2 for more than that. Are you suggesting adding acid everyday?
 

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Here is a thread and link that explains "Calcium Nodules" which indicates that the plaster is losing its' bond to the underlying substrate, which is also known as delamination. Calcium Nodules in pools

In time, the plaster coat may break away and fall off the walls in small chunks if bad enough. Tapping the area where the white nodules are will make a hollow sound (indicating the delamination) and can be compared to where there aren't any nodules.

In regards to the massive white spotting that looks like calcium scale; note that the calcium level has been rising dramatically. When scale develops on the pool surface, the calcium level of the pool water does not go up, but will lower or at least stay the same due to the calcium precipitating out of the water and depositing onto the surface. I believe that part of the reason the calcium level is rising is due to the poor plaster surface that is deteriorating and the plaster material is dissolving into the pool water, thereby increasing the calcium level of the pool water.

To determine which it is, you can try sanding off the white areas with some sandpaper and see if the white discoloration is easily and quickly removed. If it doesn't come off easily, then it isn't scale. Recently formed scale on a new plaster pool will come off easily.
 
Here is a thread and link that explains "Calcium Nodules" which indicates that the plaster is losing its' bond to the underlying substrate, which is also known as delamination. Calcium Nodules in pools

In time, the plaster coat may break away and fall off the walls in small chunks if bad enough. Tapping the area where the white nodules are will make a hollow sound (indicating the delamination) and can be compared to where there aren't any nodules.

In regards to the massive white spotting that looks like calcium scale; note that the calcium level has been rising dramatically. When scale develops on the pool surface, the calcium level of the pool water does not go up, but will lower or at least stay the same due to the calcium precipitating out of the water and depositing onto the surface. I believe that the reason the calcium level rising is due to the poor plaster surface that is deteriorating and the plaster material is dissolving into the pool water, thereby increasing the calcium level of the pool water.

To determine which it is, you can try sanding off the white areas with some sandpaper and see if the white discoloration is easily and quickly removed. If it doesn't come off easily, then it isn't scale. Recently formed scale on a new plaster pool will come off easily.

I tried getting the spotting off with a pumice stone and could not tell any difference. I didn't want to scrub too hard but the pumice stone did get off some rough spots on the benches easily (no discoloration there, just some rough patches of plaster) and thought that if the white spots were scale it would come off fairly easily or at least I would see a difference, which I did not. I will try sandpaper to see if that is any different.

i will also tap the plaster, which I haven't done yet. I am sure the calcium drips are nodules. They easily scrape off with my fingernail and quickly dissolve or break apart in my fingers and more are popping up as the days go by.

The calcium hardness rising in my pool has really bothered me...it just doesn't make sense with the fairly good amount of rain we have gotten here this spring/ summer. Not a crazy amount but enough to dilute the CYA and chlorine.
 
Use the hard plastic hand side of a screwdriver to tap the plaster surface.

You will now be able to show the plastering contractor that the plaster defects is not calcium scale or anything to do with water chemistry balancing.

If they claim that the plaster surface is etched by aggressive pool water, point out the smooth dark and unaffected areas of the plaster surface as not being etched. Point out that aggressive water would uniformly etch the plaster surface. Also, aggressive water would not form hard calcium nodules on the surface. The most likely reason for the calcium level constantly rising is because plaster material is dissolving off and into the water.
 
Use the hard plastic hand side of a screwdriver to tap the plaster surface.

You will now be able to show the plastering contractor that the plaster defects is not calcium scale or anything to do with water chemistry balancing.

If they claim that the plaster surface is etched by aggressive pool water, point out the smooth dark and unaffected areas of the plaster surface as not being etched. Point out that aggressive water would uniformly etch the plaster surface. Also, aggressive water would not form hard calcium nodules on the surface. The most likely reason for the calcium level constantly rising is because plaster material is dissolving off and into the water.

Thank you. That is exactly what I needed to know - how to say what I need to say to make my case. Much appreciated.

So if it were scale would it be all over the pool correct? The walls are free from the spotting. It's the bottom of the pool and around the curve of the pool floor as it turns into the sides where the spotting is making it look like it's starting to creep up the walls. The spotting is also on the bench seats and step out.
 
Yes, when the pool water IS out of balance (above 0.6 CSI) and IF scale develops, it will do so everywhere and uniformly.
When pool water is aggressive (below -0.5 CSI) it will also uniformly etch a plaster surface, and would take a long time to visibly do so, and would not do so in spots, not in streaks, or in some parts of the pool and not other areas IF the plaster workmanship was done properly everywhere.
Do not accept the suggestion that the water has been out of balance.
Further, since the pumice stone did not remove the whitish spots, that indicates that the problem is not calcium scaling.
Nodules forming sporadically and randomly also indicates that water chemistry is not the problem.
Tapping where nodules exists and the hollow sound is the final indication that the new plaster finish did not properly bond to the substrate.
Also, look (very closely) for small cracks where the nodules have formed on the plaster surface. That is another symptom of bond failure and delamination.
The formation of nodules also causes the calcium level to increase in pool water.
 
Ph is constantly rising, which I add MA when it rises to 8 (sometimes it's 8 +, like after it rains or I missed a day of checking) to lower to 7.4 or 7.5 ( this cycle is about every 3-4 days). It doesn't seem to help me much to try to lower it to 7.2. It seems to take the same amount of time to rise to 8. The TA hasn't been over 110 except for once. I have it down to 80 right now. I don't think my csi has been over .6 but it's gotten close a few times. Nor do I think it's ever been -0.5. It's been -0.3. I have records and they want to see them.

Besides the nodules the pool walls look beautiful. Smooth and the right color.

i will get in the pool today, trynsandpaper and tap around the nodules. I'll let you know what I discover.

Thanks so much for your help!
Linda
 
Yes, when the pool water IS out of balance (above 0.6 CSI) and IF scale develops, it will do so everywhere and uniformly.
When pool water is aggressive (below -0.5 CSI) it will also uniformly etch a plaster surface, and would take a long time to visibly do so, and would not do so in spots, not in streaks, or in some parts of the pool and not other areas IF the plaster workmanship was done properly everywhere.
Do not accept the suggestion that the water has been out of balance.
Further, since the pumice stone did not remove the whitish spots, that indicates that the problem is not calcium scaling.
Nodules forming sporadically and randomly also indicates that water chemistry is not the problem.
Tapping where nodules exists and the hollow sound is the final indication that the new plaster finish did not properly bond to the substrate.
Also, look (very closely) for small cracks where the nodules have formed on the plaster surface. That is another symptom of bond failure and delamination.
The formation of nodules also causes the calcium level to increase in pool water.

Onbalance,

i used sandpaper and the pumice stone again and there was there was no difference. Nothing came off at all. I really looked at the side of the pool and they look good for the most part. A few places around one of the lights has some discoloration.

As far as the nodules. A few of the places sounded a bit more hollow but most of the time I couldn't tell a difference. I need to get one of my kids out there with me. There are two or three larger nodules a bit deeper on the sides and one of them sounded hollowed. My eyesight under water isn't so good so I couldn't see any cracks. But again, the nodules come off easily by scraping my fingernail over them.

I'll keep you posted on what plasterer says. The pool builder has asked for my chemical records. I don't have records for every single day but a minimum of twoce a week. Does that seem reasonable?
 
The larger nodules will have a larger area of delamination (surrounding the nodule) and will have a greater hollow sound than will small nodules, so that is typical.
Once or twice-a-week water tests is absolutely sufficient for documenting the water balance.
The CSI is the most important and most relevant factor that determines whether the pool water is balanced or not, not the individuals chemistry parameters. Therefore, a pH of 8.0 to 8.4 does not cause calcium scaling as long as the CSI is within the proper range. And I am adamant about that. Do not let the contractor suggest otherwise.

Calcium nodules emit from a pinhole and/or small crack and from a void below the layer of plaster. They are not caused by out of balance or scale forming water.
Be confident in your position because you have the evidence that the plaster workmanship was not up to par. I am hopeful that they will come to the same conclusion.

Finally, but wait to throw this out, if you get a final push-back from the contractor, ask how much "calcium chloride" was added to the plaster mix. And that you can easily have the plaster analyzed for that information. And tell them that Calcium chloride should NOT be added to plaster that contains a color pigment which your plaster does.
 
I'll get my teenage kids in there tomorrow to go down where the bigger nodules are and give it a look. I've hesitated knocking any of them off because I want the plasterer to see them.

That is is very helpful information. Thank you!
 

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