raised stains, stained bumps

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J

Johnny B

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LifeTime Supporter
Mar 19, 2009
591
Charlotte, NC
I have some funky stains, Saw them upon opening & hoped they go away.
About 10, scattered all over.
None bigger than half the size of a dollar bill, most about the size of a silver dollar or a tad bigger.
They are raised. Looks like mountains on a topographical map, the peak being cleanest/most white like plaster& the base being darkest. As if a glob of something was dropped on the surface /got through the winter mesh cover & sunk then stuck to the bottom & chemically boned to the bottom.
Brown in color.
Put a chlorine puck on one for 40 minutes with no change.

Water is pretty cold so haven’t gone in; did run the plastic frame of the net over one & it seemed to scrape off a bit of the color & therefore perhaps some of the bump. My force was not great, but it did verify the definite raised /bump/bumpiness

Any suggestions?

Thanks
 
How does one do that just on a bottom spot?

pH 7.5, it rises & I keep it in range, it was 8.2+ upon opening 4 weeks ago
FC 4+ daily
CC 0
CYA 30 (2 week ago)
Borates 30 (3 weeks ago)
TA 90 4 weeks ago upon opening, 2 weeks ago TA was 60 so Targeted TA of 80, a week later TA was again 60 so again targeted TA 80 again & I’ll test it in 3 days unless you want it sooner
CH 250 4 weeks ago upon opening

Also I have some type of brick/pool-stone shaped like a brick (for tile? no idea). Any help?

I have 3M wet-dry sandpaper too. Or this should be treated chemically (not physically rubbed/altered)
 
I can do that. You guys want 7.0 or 7.2?
I’m going to wait for Jason or others to reply since from Jason’s post it sounded like there was some way to spot treat these areas.
FWIW,:TA 90 5 weeks ago upon opening,
3 weeks ago TA was 60 so Targeted TA of 80,
a week later TA was again 60 so again targeted TA 80
tested 9 days later (yesterday) TA was 70, my range should be TA 70-90.
do you want me to get it to 80 or 90? If so, after the week of acid & brushing or just a half hours or so after adding the acid the 1st time?
I just dropped the pH to 7.5 2days ago (and confirmed it yesterday); I do remember you guys once advising to do the acid in 2 separate half increments (re-test an hour after the 1st dose) to be sure you don’t goof so I can do that if that still applies in this situation.

All the plaster has a “dirty/non-white” look to it. Is this related? Hard to tell if it’s just a sunlight issue but I’m pretty sure it looks less white than last year.

Finally & most importantly, how do I prevent this in the future?
Is the cause of all this a pH too high for too long? Over the winter? I should have tested over the winter & added acid?

Thanks
 
Morning! the color of the plaster could be related - could be caused by the PH rising over the winter. It's not a good idea to add acid unless you have a way you can circulate the water?

If your TA is 70 that's fine - the range of 70-90 means 70 is ok
Acid lowers your TA - so when you add acid to lower the PH the TA goes down too - you are doing the correct thing, just occasionally bump it with Baking Soda if it goes below 60.

PH 7.0-7.2 is fine either- it doesn't have to be precise.
 
Will do & Thanks .
Do I need to check the TA sooner than 1 week from yesterday because of my action to lower pH to 7.0? Or I should test TA & get it to 70 sooner, like the same day I add the acid?

From pool School:

TA - Total Alkalinity

Total alkalinity indicates the water's ability to buffer pH changes. Buffering means you need to use a larger quantity of a chemical to change the pH. At low TA levels, the pH tends to swing around wildly. At high TA levels, the pH tends to drift up. TA contributes to the CSI which indicates the tendency for plaster damage or calcium scaling.

The ideal TA level depends on several factors. If you are using acidic chlorine sources, such as trichlor or dichlor, keep TA on the high side, perhaps between 100 and 120. If you have a SWG, or if you commonly run water features such as a spa, waterfall, or fountain, keep TA on the low side, between 60 and 80. Otherwise levels between 70 and 90 are good. Pools with plaster surfaces should factor their CSI into the preferred TA level decision. Pools with vinyl liners can tolerate high TA levels reasonably well.

You can raise TA with baking soda. It is often best to make large TA adjustments in a couple of steps, testing the water after each one, as adding baking soda will also affect the pH and you don't want the pH going out of range. If you need to lower your TA level, see How To Lower Total Alkalinity.


"TA contributes to the CSI which indicates the tendency for plaster damage or calcium scaling."
How? Lower or higher TA is more likely to damage plaster?
My ph creeps up all yr., acid needed every 7-10 days, last season my TA was 90 I believe. This yr at opening TA was 90 but was 60 at later tests till yesterday where it was 70, which I know you say is fine, but after solving this issue, based on my history, the preferred TA fo me is 70 or 90 or makes no difference?
70 is a better TA goal for me or not?
 
As long as you are in the range you are fine - CSI is a complicated issue that most pool owners shouldn't have to worry about as long as they keep their water at the recommended levels.

So for your case, if you are having to add acid often, try maintaining your TA around 70, see if that helps the PH drift subside a little.

Higher TA combined with high CH and high PH can cause scale. Low PH and Low TA and Low CH can cause plaster damage, but it's not clear how long a period these conditions have to exist before that can occur. Scale can occur quicker than plaster degredation, I believe.

Jason would know better as far as if you need to be more precise but I don't believe so. I'm sure he'll chime in when he can.
 

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Yep.

TA around 70 is just fine. The difference between a TA of 70 and 90 is fairly small. The higher TA will tend to cause PH to rise more, but if you don't have a SWG or fountain or waterfall that difference is usually not significant.
 
You could possibly have some metal staining and/or metal staining on the scale. It sounds like you probably do have calcium scaling. When I did the AA treatment, last fall, I had a lot of scale on my blue plaster. My stains were metal, mostly from iron. On the white scale it was a tan color. It took longer for the stains to release on the scale than it did on my plaster, too.

Has anyone suggested putting Vit C tablets around several areas of the bottom of your pool to test for metal staining? The tablets will lighten the stain right where the tablet has been but in some cases there will be a black streak coming off the test area. It will go away.

When you test with the Vit C tablets, turn everything off to get the water very still. Don't disturb the tablets. Let them dissolve totally. I got different results at different areas of the pool. In the deep end is where I got the black streaks running towards the bottom drain.

gg=alice
 
I could have written the OP's post - half a dozen raised brown bumps.

ph = 7.6-7.8 (got up to 8.0-8.2 over the winter)
SWG system
Alk = 80
ch=420 (per tfp test kit)

Same treatment regimen? lower pH to 7.0 and brush for a while?
The p.o. left a "stain eraser" in the garage - Tackle them with it?
 
acroy said:
Same treatment regimen? lower pH to 7.0 and brush for a while?
The p.o. left a "stain eraser" in the garage - Tackle them with it?
Click to expand...

I've never gotten any results with the "stain erasers", the little rubber/gritty things you attach to a pole, other than on organic stains.

See the post about posting a picture of yourself. You'll see some of the scale I've delt with over the years, untill I found TFP, that is. :whoot:
 
After much brushing time & acid & baking soda & testing reagents, I see no change of the stains. Perhaps all the non-stained plaster areas benefited?
Tomorrow is 7 days of keeping the pH at 7-7.2, actually closer to 10 days but the one of the early days I let the pH get to 7.5 until I got a handle on it, so practically 10 days.
Any suggestions?

In the meantime, I’m doing a search on "acid wash for calcium staining"

It is ok to discontinue my low pH Treatment or you want me to stick with it a bit longer?

Thanks as always
 
I serched TFP on this.
I read: If you have dry acid, you can put some in an old sock, tie a knot, and set it on the stains, see if that changes anything.
I’d like to try this unless you guys advice against it.

Questions:
I’m after muriatic acid?
%/concentration?
I get it at Lowes?
I should remove the acid-filled sock off the stain in 3 minutes or 20 minutes or 3 hours? I know I’ll be eating plaster away & I don’t want to go beyond what is necessary. Whatever you advise I’ll be checking it sooner than advised to be on the safe side, but was hoping for a general time frame. I won’t leave it overnight for sure. I have no problem going to bottom & scrubbing with gloved hands & eye goggles unless that is not advised.

Thanks
 
You are looking for Dry Acid - "PH Down" sodium bisulphate. You leave it on the spots for 45 minutes check for changes every 15 minutes. Check pool stores/pool departments for the product. You might need to use something to weigh it down...
 
The esthetics of this Cal scaling issue is acceptable. To review, There are these few dark stained raised bumps, and, the rest of the plaster is not jet white, looks “dirty” but is not/ won’t brush away.
Is there any harm is just leaving it until I am ready to have the plaster re-done in a few years or is that a bad idea?

Is the process halted if the chemistry stays balanced? Or does it worsen no matter what?

Am I correct that the cause of this was a too high pH for too long, most lkely over the winter (I first saw them upon spring opening this yr)? If yes, I'll post my plans on how I would like to keep the pH balanced in future winters to see if it is a sound idea.

Thanks
 
There is no harm to the pool to leave calcium scale in place aside from the visual appearance.

As long as your chemistry remains balanced the scaling will not get better or worse.

High PH is by far the most likely cause. Your theory about high PH over the winter is very likely, but difficult to prove.
 

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