Reviving black pool grout, suggestions?

[a1sysman]

Good afternoon all

Out black grouting on the bottom of our pool no longer looks jet black, now more of a gtey in places. Pool walls grouting still looks to be an aceptable black.

Looking for suggestions as to cause and remedy please.

TIA

[Keithcaley]

I can't say that I've seen this myself, and if anyone more knowledgeable comes along with a suggestion, I'll happily bow to them...

My first thought was a combination of sunlight and chlorine - given that the bottom of the pool probably gets more sunlight than the sides. Regrouting would solve that one.

My Second thought was efflorescence from the concrete pool structure migrating into the grouting, which would imply that the 'isolation' - rubbery waterproof coating - between the concrete base and the tiles had failed in places. This would be more of a job - strip off all of the tiles and isolation, re-apply isolation and re-lay the tiles and regrout.

I can't think of any other cause, and even if you tried to darken the grout artificially with some waterproof colourant (if such a thing exists!) it would mean draining the pool.

I really hope that someone comes up with a simpler explanation and solution!

[Keithcaley]

Just a thought - you could try using a long pole with a scraper attached to the end, and try scraping the surface of the discoloured grout in a small area, to see whether the discolouration is just on the top surface or coming up from below - that might at least give you a clue...

[Soner]

I have similar issue, but my pool was recently retiled with black grouting. Where they did not clear the cement between the tiles properly before grouting these areas are now grey. As they were not cleared properly, only a thin layer of black grout was covered over, which has very soon come off.

[Keithcaley]

Do you clean the pool yourself or employ a pool cleaner? - in either case, when chlorine is added to the pool, is it evenly distributed over the entire source, or dumped in the general area(s) where the discolouration is occurring? Excessive concentration of Chlorine in specific areas could be the answer in that case.

[a1sysman]

Do you clean the pool yourself or employ a pool cleaner? - in either case, when chlorine is added to the pool, is it evenly distributed over the entire source, or dumped in the general area(s) where the discolouration is occurring? Excessive concentration of Chlorine in specific areas could be the answer in that case.

Thank you for your thoughts Keith.

I clean the pool myself. When adding chlorine I do not just dump the chlorine straight into the pool, rather I walk around the pool spreading the chlorine relatively evenly.

I did wonder if the chlorine had eaten away at the black grout on the bottom of the pool - the greyness covers so much of the bottom I am doubtful this may be the cause, albeit I have not dismissed the possibility.

[a1sysman]

Just a thought - you could try using a long pole with a scraper attached to the end, and try scraping the surface of the discoloured grout in a small area, to see whether the discolouration is just on the top surface or coming up from below - that might at least give you a clue...

Our pool has a below water line seat across the width and steps down. The discolouration affects these areas as well as the pool bottom itself. Less so the pool wall and upsides to the steps.

I have a metal pool brush I have gently used across the glass tiles and grout. I have tested a Stanley blade scrape across the grout lines, again with little or no improvement.

I don't know if there are any pool experts here (in NC) who can genuinely advise without seeing this as simply a business opportunity to suggest regrouting, or worse, taking off the tiles and redoing the isolation, relaying the tiles and then regrouting.

I was hoping there may be an additive to put into the water over the winter that may be able to "clean off" any growth or staining afflicting the pool bottom grout, before use again next year.

Draining the pool and relaying has to be the last resort I would think.

[Keithcaley]

I'll ask my pool man if he has any ideas the next time that I see him - it may be a few days 'cos I'm sometimes out when he calls.

Actually, you could call in at a few pool supply shops and ask them if they have come across this before - Best of Luck!

[a1sysman]

I'll ask my pool man if he has any ideas the next time that I see him - it may be a few days 'cos I'm sometimes out when he calls.

Actually, you could call in at a few pool supply shops and ask them if they have come across this before - Best of Luck!

Thanks again Keith. Yes, I will ask around too.

[sophie]

My pool man says that our black grouting shouldn't be black!! He says ours was white and the white grouting has come out over the years , showing the black cement stuff underneath.

[a1sysman]

I have similar issue, but my pool was recently retiled with black grouting. Where they did not clear the cement between the tiles properly before grouting these areas are now grey. As they were not cleared properly, only a thin layer of black grout was covered over, which has very soon come off.

Living with it or having it done again?

[Soner]

Living with it. I give up. Had pool tiled in mosaic tiles 5 years ago and started coming off within first month. Now had pool re-tiled and not sure if tiles are proper Pool tiles as they are discolouring and black grout turning grey. Will wait another 5 years before I attempt retiling or re-grouting. You live and you learn....
Can't let things like this bring me down, not worth it.

[frontalman]

I've never seen a pool with black grout. Ours is white and still looks pretty good after more than 14 years. Our drain grille has come adrift but we just manually place it back in place with the pool pole. Our pool man replaced a tile and re-fixed the grille by diving underwater and remained on the bottom for some time. How he did it still baffles me. The tile is still sound, but the adhesive only lasted about nine months on the pool grille. I suppose at some point we will have to drain to do these and any further repairs.

[sophie]

We'll have to drain at some time because after 15plus years the lights stopped working and have now come away from the side of the pool. The fixings on the pool side and on the rear of the lights have just rusted away. Also the pool man has gradually broken all four filters on the bottom because of hitting them too hard when "hoovering". He says they all crack and break up eventually.