Help needed on Honed slate floor with UFH

[AliGage]

Hi guys and girls,

Desperate for a bit of help. I've just finished a honed slate floor with electric UFH in a thin coat of SLC.
Everything went fantastic, and it looks stunning. However, although sealled i seem to have two tiles where the honing of the tile is pretty poor. I've not noticed this until after the floor has been cleaned, sealled and everything else. Unfortunately these two tiles have sucked in a bit of the grout.

I've tried my own cleaners on it but to no avail. Can anyone suggest an impregnating cleaner that may lift the residue out. I really want to avoid lifting the tiles but can if necessary. I'm absolutely gutted, the floor otherwise looks great. Typically these two tiles are slap bang in the middle of the floor.

I've got to shot back out now but ill post a couple of pictures later of the two tiles. But the floor itself is posted on my facebook page (link in my signature)

 

[kilty55]

might be quicker just replacing the tiles mate?

 

[White Room]

As above would be my choice....

 

[AliGage]

I've thought about that, and would have no problem doing so. Trying not to inconvinience the customer. He has guests coming over Christmas, any delays prolongs the switch on of the UFH. Customers happy to leave it until the New Year to replace them both, but i'm unhappy about leaving the eyesore for his guests to spot as they're admiring the new floor. Here's a couple of pictures. I'm doing some tests at home i'm managing to clean the slate with a super remover and i don't appear to be damaging the slate, leaves awlful white residue though, but then using HG's super remover it appears to clean this up. The only bit i don't know is if Fila's Extra Strong residue remover (that is advised not to be used on this product) will remove the ingrained grout.

Like i say tiles will be replaced if need be, just can't really be done before the New Year and i'm not happy leaving it this way over Christmas whilst he has guests staying.

 

[AliGage]

Just an update. I've tried a combination of a few cleaners today after testing at home. It's cleaned the tile fine without any damage but the stain still remains. Should be getting a few pieces in the next 48 hours to replace and told my customer i'll get them changed as soon as i have time to get to him. I hate being caught between jobs like this. Thankfully he's easy going and pleased with the floor as a whole anyway. Even said to sort it in the new year but i just don't like the idea of his family and guests over xmas having to see it.

Anyway ill sort it this week, i am keen to know of solutions to this though. If anybody has any. I'm going to try and get a good size piece out so i can trial some products at home. Any ideas?