Excessive sand in filter, 1+ years after refinish?

[BMoreE]

Had our rebuild done last June, and got the "Ansylbrite" quartz finish (the Anthony/Sylvan branding.)

I've had an issue with pH drifting up from 7.6 to over 8.0 constantly ever since last season (see thread: New Plaster with pH drift but want to close) and it kept up this season, albeit slowing somewhat. I only had to put in 4 gallons of Muriatic over the ~4 months or so I had it open this year.

Using BBB all the pool's life - pretty low CYA (~40) from 3" tabs in the feeder, but high calcium (~450), Alkalinity 80.

In any case, at closing I pulled out my cartridge filters and cleaned them as usual. However this year a TON of white sand (see pic) spilled out of them - probably a half-gallon worth at least! I can only assume this came out of the new finish over time. We've had this pool for 15 years, and never had this kind of sand filtering out of the original finish, which was a regular white gunite.

It's making me think they botched the mix somehow. Any ideas before I once again call the builder? Is this common?

 

[YippeeSkippy]

I'm not familiar with this Ansylbrite finish.... gonna dip in to the archives and see if anyone else has mentioned it.

Can you take some of that stuff and pour a few drops of muriatic acid over it, and tell us if it bubbles?

Which pucks are you using? I just want to rule out that its not some undissolved puck byproduct?

Maddie

 

[kimkats]

Maddie said just what I was going to say to do.

 

[Bperry]

Had our rebuild done last June, and got the "Ansylbrite" quartz finish (the Anthony/Sylvan branding.)

I've had an issue with pH drifting up from 7.6 to over 8.0 constantly ever since last season (see thread: New Plaster with pH drift but want to close) and it kept up this season, albeit slowing somewhat. I only had to put in 4 gallons of Muriatic over the ~4 months or so I had it open this year.

Using BBB all the pool's life - pretty low CYA (~40) from 3" tabs in the feeder, but high calcium (~450), Alkalinity 80.

In any case, at closing I pulled out my cartridge filters and cleaned them as usual. However this year a TON of white sand (see pic) spilled out of them - probably a half-gallon worth at least! I can only assume this came out of the new finish over time. We've had this pool for 15 years, and never had this kind of sand filtering out of the original finish, which was a regular white gunite.

It's making me think they botched the mix somehow. Any ideas before I once again call the builder? Is this common?

If you lower your alkalinity to 50-60 the pH rise will slow down even more. Calcium is not very high at 450, I generally keep mine around 550ppm.

As mentioned above, find out if it’s sand or calcium scale but using some acid.

 

[BMoreE]

I’ll definitely try that out, thanks for the quick replies. Won’t be back to the house for a week tho… stay tuned!

 

[Cena_sea]

When our builder cleaned the cartridge filter shortly after plaster I remember there being chunks of plaster— but it was noticeable because it was blue. This is white though. But it looked kind of like that. However it never continued after.

 

[BMoreE]

Can you take some of that stuff and pour a few drops of muriatic acid over it, and tell us if it bubbles?

Double double, toil and trouble! It bubbled up like a root-beer float with mentos. So what does that mean?

Which pucks are you using? I just want to rule out that its not some undissolved puck byproduct?

I threw the canister away so I'm not completely positive, but I think they were the Clorox "99% trichlor" tabs, the plain ones, not the "Xtra blue."

 

[BMoreE]

When our builder cleaned the cartridge filter shortly after plaster I remember there being chunks of plaster— but it was noticeable because it was blue. This is white though. But it looked kind of like that. However it never continued after.

VERY white sand... I'd love to be on a beach that looked like it.

 

[Bperry]

Double double, toil and trouble! It bubbled up like a root-beer float with mentos. So what does that mean?

That means it’s calcium.

 

[BMoreE]

That means it’s calcium.

And so what does THAT mean? My assumption was it's coming out of the new finish, so does that mean I'm destined for a pitted/rough surface after spending thousands on a refurb? What could cause that (did they screw up the finish mix? the application?) Can I stop it from happening? (Maybe by lowering Alkalinity as you suggested earlier?)

Note that it is now 15 months after they finished the refurb (and I closed the pool for the season.)

 

[duraleigh]

After 15 months, what's done to the finish is done and I see no easy way to restore it.......others may have a different opinion.

The cause might have been plaster but it equally could've been from chronically low pH of your pool water. If you have used the puck feeder for your chlorination, that may have driven your pH excessively low allowing calcium to leach from your plaster.

 

[BMoreE]

Interesting... so actually my pH has been chronically high since the refurb, as it continually drifted up over the measurable 8.0 with my Taylor kit. (and which, in response, I'd add muriatic based on the demand required to bring it back to the 7.6 range.)

Perhaps my definition of "high" has been incorrect, and I should allow it to target the higher ~7.8 range during normal operations? It really is confounding to me, as I thought I had been overly attentive to the pH drift after opening. (My pool builder even commented that "you don't really need to be testing so much" lol...)

The chlorine demand was pretty low this year as we barely used the pool - it was mostly covered so keeping a 2-3 FC value was easy and I only needed to put in 4-6 pucks every 3-4 weeks.

 

[Newdude]

The calcium is clearly calcium but is there any chance the sand is paver sand washing in with runoff ?

 

[BMoreE]

The calcium is clearly calcium but is there any chance the sand is paver sand washing in with runoff ?

I'll guess this is unlikely due to the fact that we have an auto-cover always on the pool (unless I'm servicing it - no one used it all summer!) The cover attached underneath the coping pavers, so I suppose there is some potential exposure there, but I wouldn't think it enough to produce that volume.

 

[JamesW]

Plaster is made from cement and aggregate.

Ansylbrite contains quartz aggregate.

Marbelite contains marble aggregate, which is a type of calcium carbonate.

The sand is probably aggregate and the bubbling means that it is probably marbelite and not quartz.

Go to the builder and ask for a handful of quartz aggregate and a handful of marble aggregate and see which aggregate matches your sand.

While Marbelite and Ansylbrite have been the preferred finishes for years, the new aggregate finishes offer an even broader selection of textures, from fine to coarse, and are available in a full rainbow of colors.

Ansylbrite​

Ansylbrite is a popular, durable pool finish that consists of crushed quartz which enhances the density of the concrete mixture. This quartz finish provides a very smooth, glossy, and clean appearance and feel to pool interiors. Color can be added to this mixture, making it customizable and can enhance the overall look of your backyard pool.

Aggregate​

Aggregate pool finishes are becoming increasingly popular because of the versatility that they offer. From polished to exposed, aggregate offers a one-of-a-kind pool look with a beautiful array of colors and textures. This new generation of pool surfaces consists of white or colored plaster mixed with small pieces of quartz, granite, river stones, or glass beads. This luxurious pool finish is harder and more resistant to chemicals and staining than other pool finishes like plaster, so it’s more durable.

Marbelite​

Marbelite is a common pool finish that is a stronger material than conventional concrete while still staying flexible and durable. Marbelite transforms the shell of the pool to a neutral color when applied and appears blue when filled. It’s smooth, hand trowelled and built to last.

https://anthonysylvan.com/pool-options/pool-finishes/concrete-pool-finishes/

 

[JamesW]

They probably used marbelite aggregate when you expected quartz.

The high pH is probably due to the cement dissolving, which releases calcium hydroxide and calcium carbonate.

This will cause the pH, TA and Calcium hardness to rise continuously.

If the TA and Calcium Hardness are going up by the same amount when you are not adding calcium chloride or baking soda (Sodium Bicarbonate), then the cement is probably dissolving.

The cement is what holds in the aggregate.

When the cement dissolves, the aggregate falls out.

Most likely the cement has some sort of defect, which could be from several different causes like too much water in the plaster mix or a bad ratio of cement to aggregate etc.

 

[JamesW]

Rapid pH increase with SWCG

Guys, I'm losing my mind with this pool. I've scoured all the threads on this topic here and in other forums. I've tried every "remedy" I could find, and yet, here I am, dumping gallons of acid in at a time only to come back a few days later to pH > 8.0. I've always felt I was very diligent with...

www.troublefreepool.com

Plaster Installation and Maintenance - Further Reading

www.troublefreepool.com

Ten Guidelines for Quality Pool Plaster

There are proper steps to follow for the making of durable pool plaster. There are also improper practices that can lead to early deterioration or discoloration. Following is a ten-point checklist that will help achieve a lasting and discoloration free plaster. 1. The best cement/aggregate...

www.troublefreepool.com

The best cement/aggregate ratio is about one part cement to 1.5-1.75 parts aggregate (marble sand). If the plaster is too rich (cement-heavy), it tends to shrink and crack. If it's too lean (more sand), it will be less durable and potentially unworkable. Note: Always select high-quality and appropriate-grade cement and aggregate.

2. When mixing plaster, a thick mix is best. Shoot for a water/cement ratio of .48 or less. Both the American Concrete Institute (ACI) and the Portland Cement Association (PCA) maintain that lower water/cement ratios produce better-quality cement that can withstand occasional exposure to mild acids.

Lower water/cement ratios boost density while reducing permeability, porosity, shrinkage (craze cracking) and water movement within the cement product. Higher water/cement ratios, by contrast, cause excess shrinkage and cracking, and fail to offer adequate protection or long-term durability against the effects of water and the environment.

Diagnosing Pool Plaster Problems

Plaster Discolorations – New white pool plaster can discolor (darken or turn gray) from adding excessive calcium chloride set accelerator, from late hard troweling, from thin and thick areas due to an uneven shell, etc. Gray (or grey) mottled discoloration (also known as “water entrapment” or...

www.troublefreepool.com

 

[BMoreE]

They probably used marbelite aggregate when you expected quartz.

....

Most likely the cement has some sort of defect, which could be from several different causes like too much water in the plaster mix or a bad ratio of cement to aggregate etc.

Ooof, well this is what I am fearing (a defect of some sort.) I definitely paid for Ansylbrite as listed on the contract, and it has the quartz flecks throughout so it looks like the thing that the brochure said it would be.

I don't believe the Calcium readings have risen much this year - they went up within the first few months of application last year to the current ~450 where it's held ever since. Same with Alkalinity - initial rise, then steady. I just read the whole thread from flippinGeo and can feel his pain (!!) but hopefully am not in that situation as I only had pH rise all year, not the calcium/Alk readings.

Perhaps the initial curing period extended through last year's off-season, and finished up after I opened this year, and the resulting sediment is "done"? I didn't have to clean my filters after once or twice at opening as the pressure held steady all year (probably due to the lack of use of the pool, and keeping it covered.)

This is a mystery I'm afraid I won't have resolution on until next year, with clear filters to see what shakes out (or hopefully doesn't any longer!)

Thank you all for your inputs and ideas - really a great community of smart folks.

 

[JamesW]

I definitely paid for Ansylbrite as listed on the contract, and it has the quartz flecks throughout so it looks like the thing that the brochure said it would be.

Maybe they mixed marbelite and quartz?

If the sand bubbles with acid, then it is probably calcium carbonate.

Quartz does not react with acid.

Put some of the sand in acid to see if some dissolves and some does not.

Clean, dry and weigh the sample before putting it in acid and then clean, dry and weigh any remaining sand that does not dissolve to see what percentage is calcium carbonate vs. quartz.

For example, if only half of the sand dissolves, then the aggregate is probably a 50/50 mix of quartz and marble.

Stop by the builder and ask for a cup of marbelite aggregate and a cup of quartz aggregate to compare to what you have.

Try acid on some of each sample and see what reaction each has with acid.

 

[BMoreE]

Thank James - so does my action plan change based on that determination (marbelite vs. quartz?) or is that just to figure out if the builder put in the wrong material?

I don't think my builder has a location for me to stop by - it's Anthony-Sylvan, and I'm pretty sure they were just a GC subbing the work to various local crews. I also don't have a way to weigh small amounts to do the experiment on my sand (my breaking-bad years are well in my past )