Newbie, new(ish) pool, grout dissolving. Scared

Pool Snake

Member
Feb 19, 2019
12
Mexico
Hello everyone. I need some help. I have a large in ground with those small 1 cm tiles, grouted in with regular pool grout. It's about 4 years old and I am certain the grout is dissolving, breaking down:cry:. I can actually use my fingernail and scrap it out rather easily, this all below the water line. If I take my hand and rub the wall, powder/ grout dust comes off readily. It's odd because it seems to only be the walls at are effected. My friend has suggested I drain the pool and apply a sealer, but I doubt this will slow it down much. It is possible that once, only once, I may have put too much acid it- but this still was within normal ranges, as a matter of fact, the pool is always very alkaline and it hard to get it more acidic. Is there anyone out there that can help- please?

Water is slightly brackish- saline. Water is from a well that is very shallow- a cenote for those that know what that is. Hard as heck with high calcium/limestone
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
10,418
Northern NJ
Putting too much acid in would not have affected your grout.

Do you know type of grout was used and how long it was allowed to cure before it was submerged?

If the grout is soft and coming off then nothing is going to secure it. Eventually you will need a new grout job.
 
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ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
10,418
Northern NJ
Scale from hard water should show up on the tile and plaster as well as the grout. It is also usually hard and not easily off with a finger nail.

Powder could be algae.

I would use a pointed tool and see if the grout is soft enough to scrape out. How deep does the dust go before you hit hard grout? If this a surface problem or a grout problem all the way through?

Water tests and an Overnight Chlorine Loss Test should be done.
 

Pool Snake

Member
Feb 19, 2019
12
Mexico
Putting too much acid in would not have affected your grout.

Do you know type of grout was used and how long it was allowed to cure before it was submerged?

If the grout is soft and coming off then nothing is going to secure it. Eventually you will need a new grout job.
I would need to look, but it was purchased at the home depot in Mexico. It was a standard pool grout, but I have no idea the brand. Will get this info too... THANKYOU
 

Pool Snake

Member
Feb 19, 2019
12
Mexico
Scale from hard water should show up on the tile and plaster as well as the grout. It is also usually hard and not easily off with a finger nail.

Powder could be algae.

I would use a pointed tool and see if the grout is soft enough to scrape out. How deep does the dust go before you hit hard grout? If this a surface problem or a grout problem all the way through?

Water tests and an Overnight Chlorine Loss Test should be done.
I can use my fingernail and scrap the grout right out- either the hardness has 'sucked' out something in the grout, or the acid ate it, or I just don't know what? The grout for sure is soft and powdery. Can the tiles be regrouted?
 

Pool Snake

Member
Feb 19, 2019
12
Mexico
Putting too much acid in would not have affected your grout.

Do you know type of grout was used and how long it was allowed to cure before it was submerged?

If the grout is soft and coming off then nothing is going to secure it. Eventually you will need a new grout job.
Sorry, forgot to add- it cured for maybe 2 weeks- I just remember we followed the manufactures directions. It's interesting that not all of the grout is effected. It was VERY hot when they were done, maybe the grout was drying out. Thing is, it was fine for 3 years, it's only been since I did a heavy dosing for muriatic (sp) acid. That is why I thought it may have caused it. I have always had a issue with build up on the tiles, now don't have any, but grout is soft and powdery. The water here has about 1800 ppm of hardness, mostly salt and calcium. I think it leached something out of the grout. Do you know if the tiles can be regrouted as they are? brush out whatever I can and regrout?
 

kimkats

Mod Squad
LifeTime Supporter
Jul 10, 2012
41,265
Tallahassee, FL
You are doing a good job so far. Just "talk" to us as each one posts. If you want to reply to any one person just click on the word quote under their post. You will then click on "add quotes" and it will be in your reply box.

I am not sure of the answer to your question. I am going to defer to @ajw22 as he has done this kind of thing in real life before.

Kim:kim:
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
10,418
Northern NJ
Tiles can be regrouted. Best is if pool is drained. Then old grout is scraped out and new grout then applied. Epoxy grout is the best type to use.
 

Pool Snake

Member
Feb 19, 2019
12
Mexico
I can use my fingernail and scrap the grout right out- either the hardness has 'sucked' out something in the grout, or the acid ate it, or I just don't know what? The grout for sure is soft and powdery. Can the tiles be regrouted?
Hey Kimkats, thanks for the vote of confidence, now I need to bet my head wrapped around this testing kit... get those numbers.
 

Pool Snake

Member
Feb 19, 2019
12
Mexico
Tiles can be regrouted. Best is if pool is drained. Then old grout is scraped out and new grout then applied. Epoxy grout is the best type to use.
Allen, these tiles were applied with the grout that is breaking down, so under the tiles is the same product- if I scrape out between the tiles, don't I have to worry about the stuff under the tiles? I am pretty sure that if I scrape anything out, the tile will fall off!!! That is what's happening now. I have several tiles out now. Have glued them back in. Thanks for the tip on Epoxy grout, I have no idea if that was used. It's odd that not the entire pool is effected. Does epoxy grout come in grey? The current grout is concrete grey colour. (the tiles were the kind that the surface was affixed to paper)
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
10,418
Northern NJ
Tiles should be cemented to the wall with thinset, not grout. If grout was used then you have a bigger installation problem. You have to figure out how extensive your problems are. You may need a complete retile and grout using the proper material for pools.
 

Pool Snake

Member
Feb 19, 2019
12
Mexico
You know Allen, this pool was constructed in Mexico. The product that was used was a glue/grout type product and it's fine in most places, I have a picture here of how it was applied. Not sure if it helps.
 
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