Could use some help navigating plaster issue with builder.

[Megsyperk]

Hi folks, it’s been a long time since I’ve posted here, but this community has always been a wealth of information and any time I have questions this is the first place I come. I am now kicking myself for not coming here before we started the replaster process, but alas, here I am.

We just had our pool replastered (quartz with a small bit of blue aggregate) on Monday and there are these tiny brown stains appearing all over the place. Have attached a pic of an example. At first I thought it was debris — we’ve had a couple of windy days here in Houston which has dumped in our “new” pool! But when they wouldn’t budge with a brush I realized something was up.

Texted builder, they’ll send someone out either tomorrow or Monday to have a look. The builder has been really great and the experience has been very positive. I expect that this will go smoothly; they saw my testing kit and binder (where I keep a chemical log and some instructions from pool school I printed out when we bought this house 6 years ago), I had intelligent conversations with them about water quality (thanks TFP!).

Anyway. I was reading through one of the pool school articles about new plaster startups just to make sure I’m doing everything right and came across a tidbit about abalone shells and brown staining and this seems like the likely culprit, but of course am hoping you guys can help me get my mind straight before they come over.

Yesterday was my first day attending to the pool alone, we paid the builder to do the startup. Based on what I’ve now read through, I believe it was a traditional startup. And their instructions to me said to keep water balanced, I told them I knew I needed to lean on positive side of LSI/CSI for first 30 days.

Hopefully this works, link to my pool log in PoolMath: PoolMath Logs

 

[YippeeSkippy]

I'm confused... did you add abalone shells to your mix? If not, they aren't there and not the reason for any staining.

Did they do an entire chip out of the old plaster?

Maddie

 

[Megsyperk]

Hi Maddie, I’m not sure if shells were added to the mix — I was just going by issue description alone as possible root cause.

They chipped out some of the old plaster, but not all.

 

[JoyfulNoise]

Rub the spot with a sock full of vitamin C tablets. If the stain goes away then it’s iron. If not, then lightly rub the area with a trichlor puck. If the stain fades then it’s likely organic.

 

[Megsyperk]

Tried both on one of the spots. Neither did anything.

 

[ajw22]

I think it may be calcium nodules.

Calcium Nodules in pools What are calcium nodules? In swimming pools and spas, they are small mounds, bumps, deposits, or “slag” piles of calcium carbonate which are formed from material that has been released from the plaster. The small calcium nodules are rough to the touch, hard, and generally gritty. Nodules may form singularly (far apart or sporadically), or many and close together along a crack in the plaster surface.

@onBalance

 

[Megsyperk]

Going to just post some random info that may or may not have any bearing …

• Stupidly I didn’t do my own testing of the water until Friday (Day 4) so I’m relying on the builder’s results, which on some days were communicated through my husband. He wasn’t using a test kit I’m familiar with — it was definitely Taylor, medium sized blue rectangular box.
• Filled pool had green tint to water (see pic)
• Day 1 test results from builder: FC 0, pH 8.2+, TA 180, CH 110, CYA 0. They added 64 oz. startuptec, calcium (can’t remember which one), MA.
• Day 2 test results from builder: pH 7.2, TA 110. I know they added a couple of pucks in skimmers and liquid CYA target of 30. Not sure if anything else was added. Water looks great.
• Day 3 test results from builder: FC 0, pH < 6.8, TA 110, CH 260, CYA 0. He added 5# soda ash, some liquid chlorine, added couple more pucks. Total breakdown of and cleaning of filter. Recharged with 6# DE.
• Day 4 test results with TF-100: FC .5, CC 0, pH 7.5, TA 150, CH 375, CYA 40. I’ve been adding MA as needed and TA is creeping down but I’m not overly concerned since my CSI is .3, which I understand to be good for first 30 days.

 

[Megsyperk]

Very interesting read, can nodules form that fast? We are on Day 5.

I wish I could better describe what these look like. But you can’t feel them, it’s not something that can be picked up off the plaster. It’s almost like some of the blue aggregate (is that the right word?) that are embedded in the quartz plaster are turning brownish-orange and creating stains that travel from the aggregate. Which is why the abalone shells made sense. But I take it that those must be an add-on and not included in quartzscape?

 

[JoyfulNoise]

Unless you ask for abalone (and pay for it!), you did not get abalone.

My off-the-cuff guess - their plaster pump wasn’t properly cleaned prior to use and random “crud” got mixed into the plaster and shot along with your quartz and blue aggregate.

Can you try grabbing some medium grit wet/dry sand paper from the hardware store and try sanding it down? Do it in an inconspicuous spot.

 

[ajw22]

Very interesting read, can nodules form that fast? We are on Day 5.

I didn't think so. I would not expect calcium nodules or abalone rot to develop so rapidly.

I can see streaking from the brown spot. That says it is from something soluble that flows. I would have thought iron particles but you say vitamin C does not lift the stain.

It looks like some foreign substance got into the plaster mix. You need to see what the plaster company says.

 

[Megsyperk]

Unless you ask for abalone (and pay for it!), you did not get abalone.

My off-the-cuff guess - their plaster pump wasn’t properly cleaned prior to use and random “crud” got mixed into the plaster and shot along with your quartz and blue aggregate.

Can you try grabbing some medium grit wet/dry sand paper from the hardware store and try sanding it down? Do it in an inconspicuous spot.

Then it’s not abalone!

I have pics of them shooting the plaster and some video, but likely not close enough to identify anything.

Sand paper — husband had some med grit wet/dry. I tried on a spot along the wall that isn’t quite as pronounced as the one on the stair (almost like the stain source is deeper into the plaster?) and nothing happened. Then I lightly sanded on the stair and I don’t see a difference. Full caveat I might not be sanding hard enough because I’m terrified of screwing something up.

 

[JoyfulNoise]

Then it’s not abalone!

I have pics of them shooting the plaster and some video, but likely not close enough to identify anything.

Sand paper — husband had some med grit wet/dry. I tried on a spot along the wall that isn’t quite as pronounced as the one on the stair (almost like the stain source is deeper into the plaster?) and nothing happened. Then I lightly sanded on the stair and I don’t see a difference. Full caveat I might not be sanding hard enough because I’m terrified of screwing something up.

It’s going to take a little “elbow grease” … honestly, you literally cannot screw up the plaster with a piece of sandpaper so have at it.

You know, when the guys are slinging plaster they basically throw the bags of plaster mix and aggregate up onto the mixing grate (some designs have spikes on the grate to rip into the paper bags) and rip the bags open while another guy is spraying hose water into the hopper. The plaster is mixed for a few minutes to get to the correct consistency and then the auger in the mixer reverses and pumps the plaster through the hose to the nozzle-man in the pool. The nozzle-man controls the placement of the mix while a bunch of guys trowel the plaster smooth. It’s not a very elegant process to watch and there’s plenty of opportunities for “crappola” to get incorporated into the mix if these guys aren’t careful.

If the sandpaper doesn’t work then wait for your PB. It’s on him to make this right. If he says the words “drain and acid wash the surface”, run away …

 

[Megsyperk]

I didn't think so. I would not expect calcium nodules or abalone rot to develop so rapidly.

I can see streaking from the brown spot. That says it is from something soluble that flows. I would have thought iron particles but you say vitamin C does not lift the stain.

It looks like some foreign substance got into the plaster mix. You need to see what the plaster company says.

Thanks again for the link. And I finally figured out how to quote-reply

I only did the vitamin C for about 30 sec … and I also just grabbed the remnants of the builder’s puck, which was pretty thin. Maybe I should try both again?

If it is something in the plaster, what’s the general remedy?

 

[JoyfulNoise]

Thanks again for the link. And I finally figured out how to quote-reply

I only did the vitamin C for about 30 sec … and I also just grabbed the remnants of the builder’s puck, which was pretty thin. Maybe I should try both again?

If it is something in the plaster, what’s the general remedy?

You need to leave the vitamin C on there for a good 5-10mins. The puck would just be rubbed on by hand, do not let it sit for long periods.

The remedy is - learn to love your pool the way it is, weird spots and all. If there’s something in the plaster that can’t be chemically treated then only a full chip out and redo will fix it and your PB will absolutely NOT want to do that. So he will try to do every little one-off Bandaid solution he can think of until it either satisfy you OR you stop pestering him. That’s the general MO of all pool builders. If he does an acid wash, and that will likely be his go-to solution, you risk seriously damaging or weakening the plaster surface while making it rough and more porous. See what he says …

 

[Megsyperk]

You need to leave the vitamin C on there for a good 5-10mins. The puck would just be rubbed on by hand, do not let it sit for long periods.

The remedy is - learn to love your pool the way it is, weird spots and all. If there’s something in the plaster that can’t be chemically treated then only a full chip out and redo will fix it and your PB will absolutely NOT want to do that. So he will try to do every little one-off Bandaid solution he can think of until it either satisfy you OR you stop pestering him. That’s the general MO of all pool builders. If he does an acid wash, and that will likely be his go-to solution, you risk seriously damaging or weakening the plaster surface while making it rough and more porous. See what he says …

Okay starting with vit C and puck again and will report back. Y’all are so awesome.

 

[Megsyperk]

Update, 10 min after vitamin C, I think I see a difference. It’s different lighting conditions but the “streak” is definitely faded. So this means iron, right?

 

[JoyfulNoise]

View attachment 380262Update, 10 min after vitamin C, I think I see a difference. It’s different lighting conditions but the “streak” is definitely faded. So this means iron, right?

If vitamin C is making the stain lighter then it’s most definitely iron. Talk to your PB to see what your options are. An ascorbic acid treatment might work but you want to get at the root cause a bit. If it’s some kind of iron particulates that got incorporated into the plaster, they need to be chipped out and then plaster smoothed.

 

[Megsyperk]

If vitamin C is making the stain lighter then it’s most definitely iron. Talk to your PB to see what your options are. An ascorbic acid treatment might work but you want to get at the root cause a bit. If it’s some kind of iron particulates that got incorporated into the plaster, they need to be chipped out and then plaster smoothed.

Thanks again for the assist. Will update y’all on Monday.

 

[Megsyperk]

Oh you guys. I just turned on the pool lights and I really don’t like what I see. Btw I usually have the lights on white, I’ll need to reprogram, it looks like they’re stuck between colors.

Okay back to my heart’s in my stomach — is that a calcium nodule next to the light? And the bottom looks gashed in spots and there are blister looking bumps forming.

 

[ajw22]

Pool lights show the normal imperfections. Nothing unusual about those.