can someone tell me the main difference between white and grey floor adhesive ????? and i know ones white ones grey but what i mean is why buy white adhesive that is about £5 a bag more expensive??? is it to do with possible staining tiles?? please can someone advise me

It's really a matter of the tiles that you are fixing, how clean you work and the colour of your grout. For example, if using a light coloured natural stone tile, then you should use white adhesive, due to possible staining or shadowing issues. If you are a messy worker then white will probably assist you too. If you are using a light coloured grout then you will have less chance of the adhesive showing through the grout lines or on the edges of the tiles.

thanks for that. when you read it out it seems quite obvious really and as i can be a bit messy i think its white for me.
Just one more question, can I use the adhesive up to 10mm deep? just to assist to achieve a good level finish -its a concrete floor and ceramic tiles- and also i was looking at mapei "rapid set flexible adhesive" which cost £26.99 a bag is that a good price???

You can get trade prices from tile outlets if you're a professional tiler. Trade prices can't be discussed in the public forums, but not only do you get to discuss trade prices if you get in the TilersForums Arms, you get special discounts on adhesives too!

PTB will go further but it's probably best to use SLC first on rough floors. Especially if you're newish.

what is PTB and SLC?

pourable thick bed, self leveling compound

you will get less mtrs out of bag of PTB than thin bed adhesive but most adhesives will only go up to about 6mm deep where PTB will go up to 20 mm