Had Coping and Tile redone last Fall, Pool Robot picking up lots of plaster?

[mikegmi2]

New pool owner here. Previous owners left the pool is bad shape, tiles were 50% popped off, small chunks of cement falling into the pool, and all coping stones were loose. I had this all repaired and replaced with new last fall, and opened my pool a week ago. Since then my robot has been picking up a lot of what I believe is plaster. Every day I clean the robot out and find a big glob. See photos.

Is this normal and eventually it will all get cleaned up? Or could I have a bigger problem like soft water destroying my plaster? I measured the calcium hardness to be 110-120, realized this is low, and yesterday added half a 25lb bucket of calcium, brushed, ran filter overnight.

How quickly can soft water start destroying your plaster and how much damage can it do in 1 week?

 

[ajw22]

Post a full set of water chemistry including CSI.

Water damage to plaster takes months to develop, not days.

From the timeline you posted it sounds like you closed the pool right after the replaster and didn’t give it a lot of time to filter out the plaster dust so it settled to the bottom.

 

[mikegmi2]

Ok I will get water chem results and post.

And you are correct, the pool was only filled half way after the coping and tile was replaced (the plaster was in ok shape so they only did a bit of patch work here and there to the plaster), and I simply added a winterization kit to the water, and covered the pool.

 

[ajw22]

I hope the hallway fill submerged all the repaired areas. Plaster needs to be underwater to properly cure.

 

[mikegmi2]

Didn't know that, thanks for the info. There were some small areas up by the tile line that did not get submerged. It's all been submerged fully for a week now that I have the pool open. Are those areas now compromised? Will they fully cure now that they are underwater?

 

[ajw22]

Your process was not optimal for the best curing of plaster. You will have to see what develops. Some of that plaster dust could come from repaired spots that did not properly cure and harden.

 

[ajw22]

@onBalance may have some thoughts

 

[onBalance]

The current plaster problem (the plaster material residue being removed) is very unlikely to be caused within one week.
Significantly aggressive water would dissolve plaster completely and not leave a residue on the bottom, unless the aggregate is made of quartz. Also, the current low level of CH at 110-120 ppm indicates that not a lot of calcium/plaster has been removed so far.

In addition to the request for a full set of pool water readings, it would also help to know the tap water readings for pH, alkalinity, and calcium which is needed for a complete picture. How old is the plaster, which could be simply deteriorating. from past poor maintenance?

It is also very possible that the cement/plaster/material that is being removed by the Robot cleaner could be from the tile, coping, and plaster patch work done last fall that fell into the bottom of the pool.

 

[mikegmi2]

Thanks for the reply. Here are my readings as of yesterday:

FC – 6
CC – 0
pH - 7.2
TA – 88
CH – 190
CYA – 48

I went and got another 12lbs of calcium to get me over the 200 mark, which I will be adding today. From there I shock with Cal Hypo which will gradually rise my CH level, right?

The only info I got on the plaster is from the old company that supposedly did it years ago, they said around 6-7 years ago. It does have some pitting and chips here and there...in fact just today I hard scrubbed what might be a couple small black algae spots near my steps with a metal brush. The previous owners did not care for the pool at all. When I took the cover off last summer, 40% of the tiles were missing or at the bottom of the pool, and almost every coping stone was loose. They were also adding well water to top off the pool when it got low, evidence in the red streak down the tile where the elevated spa is...but at least they had a filter on the end of the hose.

And yes, the house is on a well. Luckily there is an outdoor shower that has soft water I can use to top off the pool, as I would rather use that than fill my pool with iron.

I believe the robot is simply picking up loose plaster dust that never got cleaned up from last fall like you said. Will continue to run the robot and see what happens. Thanks!

 

[ajw22]

Mike, what test kit are you using?

 

[RickNewGuy]

Mike, what test kit are you using?

Still learning... why are you asking what kind of kit he has? Mine just came in today...

 

[mikegmi2]

Mike, what test kit are you using?

I am using the standard Taylor reagents.

 

[ajw22]

I am using the standard Taylor reagents.

That doesn’t answer what test kit you have and the range of tests you can do.

You don’t get a TA of 88 or CYA of 48 from the TF-100 or Taylor K-2006C.

 

[mikegmi2]

Oh sorry, yes those numbers specifically were provided by my local pool store. It was a more sophisticated electronic test device, which connected to the internet and then provided a print out. I don't have the print out here and cant remember the name of the device, but I can post that later if you are interested.

 

[ajw22]

Sorry, there is a difference between precision and sophistication and accuracy. We don't put any reliance on pool store testing no matter how sophisticated the equipment looks.

We are interested in test results coming from our recommended test kits and base our advice on that.