Very disappointed with Marshalls. Installed the Arrento Silver exactly as described, onto a mortar bed, and using the External Jointing Grout to finish, but we now have horrendous white staining coming through the joints every time it rains. Marshalls technician came out, said it is all installed fine, but what we had was efflorescence (salts) naturally coming through from the mortar bed. He had no idea how long it would keep going for, and he advised me to get a 'squeegee' and keep pushing the water away when it rained. I wasn't told that when buying the paving or reading the installation guides. The patio has falls to the front wall, which has the Nero Quartzite walling installed. The salt has now destroyed this, and it no longer glimmers in the sun. The technician left, promising follow up emails and advise of products to use to help to clean the salt staining, but a week on, nothing. We have spent £££'s on their product, but just get fobbed of with corporate spiel. They show the Arrento in situ while is is wet, never dry and stained. Still, as Marshalls said, just keep busy with the squeegee