Calcium Build-Up on Grout

[zollan23]

Hi everyone

Wasn't sure the best spot to post this. I've asked about calcium on tile before and have been able to get rid of the nasty spots on the tile with a pumice stone.

I'm having a lot of trouble finding a solid answer on what to do about grout. I have some really caked on calcium (see photos). I've tried super light with a pumice stone but it just starts taking the grout off. I've tried a diluted mixture of muriatic acid with a toothbrush and nothing. I tried the toothbrush with CLR and it didn't budge.

I've seen suggestions for using a chlorine tablet cracked in half but that seems more for algae (I also have no tabs as I use a SWG).

What's the best way to get this off? I've also included my most recent chemistry below. I've been through two rounds this week of lowering TA (looking to add Borates). So I've added acid to get pH to 7-7.2 and let it rise back up. This is the lowest my TA has ever been. My CH also dropped to 325 but is usually 375-350. CSI is usually very much under control.

Any thoughts are appreciated.

 

[ajw22]

It is efflorescence and has nothing to do with your pool water chemistry. Water is coming into your pool shell and out the soft grout areas and brings salts with it.

All you can do is scrape it off and try and seal the cracks in your coping that let water drain down into the bond beam.

Efflorescence - Further Reading

www.troublefreepool.com

 

[cowboycasey]

I hate to say this but that is efflorescence.. It is somewhat calcium but other stuff mostly salts in there also.. It is not from your pool water and has nothing to do with how you have your pool water...

https://www.custombuildingproducts.com/media/686946/tb21_efflorescence.pdf

 

[setsailsoon]

Z,
I had the same thing before I took over my pool right around the spillover. I think it was effervescence as others have mentioned and it was very stubborn. I typically used pumice but found accidentally that a pressure washer was much easier. Had to be careful because I could probably remove the grout accidentally but with a little care this was easy to do. Every time I power wash the pavers I check for any new material and hit it. If you get on a routine every 3-6 months it's very little effort to keep the pool looking great.

Incidentally, I looked at your test logs and csi looks good recently but 3 months ago looks like there were a lot excursions to +.3 or more. Logs don't go beyond that. Was there a change in pool maint prior to that?

 

[zollan23]

Z,
I had the same thing before I took over my pool right around the spillover. I think it was effervescence as others have mentioned and it was very stubborn. I typically used pumice but found accidentally that a pressure washer was much easier. Had to be careful because I could probably remove the grout accidentally but with a little care this was easy to do. Every time I power wash the pavers I check for any new material and hit it. If you get on a routine every 3-6 months it's very little effort to keep the pool looking great.

Incidentally, I looked at your test logs and csi looks good recently but 3 months ago looks like there were a lot excursions to +.3 or more. Logs don't go beyond that. Was there a change in pool maint prior to that?

Appreciate this. Will try hydro washing.

Far as the logs - our pool was filled on July 2nd so still very knew. Trying to find my sea legs

 

[Astro1]

Appreciate this. Will try hydro washing.

Far as the logs - our pool was filled on July 2nd so still very knew. Trying to find my sea legs

I cleaned mine today. A mixture of water and muratic acid in a spray bottle does the trick. About 2 ounces of acid per quart of water. Squirt and brush with a stiff nylon brush several times and it will clean right up.

 

[zollan23]

Thanks. I tried this previously with a toothbrush so maybe I just need something more stiff. Toothbrush and a acid/water solution did nothing for it. Appreciate the added insight.

 

[ajw22]

Thanks. I tried this previously with a toothbrush so maybe I just need something more stiff. Toothbrush and a acid/water solution did nothing for it. Appreciate the added insight.

Get a stiff brass bristled hand brush. Not steel bristles, brass.

 

[zollan23]

Get a stiff brass bristled hand brush. Not steel bristles, brass.

A brass brush wouldn't give you concerns of brushing the grout away? That's my concern.

 

[ajw22]

A brass brush wouldn't give you concerns of brushing the grout away? That's my concern.

Using an acid solution can soften the grout and remove a layer without brushing.

If you want to use this cleaning technique you need to do it carefully and hit the efflorescence without doing much to the grout.

Otherwise use a grout saw and scrape the efflorescence off without using acid. It is more work and you have to focus on the efflorescence.