I can guess Kevins answer.
Mine would be a bucket ,brush ,brick acid,bleach and a pressure washer. ( Be warned bleach and brick acid should never meet )
The stone need to be dry to apply the sealer (I have in mind).
Chris
Sometimes I lose the will to live when I see posts like this! I don't know if you do it to try and wind me up or not! For the life of me I cannot understand any Pro worth their salt advising people to use powerful building/ brick acids! Have you even considered the implications of this type of advice? Or do you think you are being helpful? If so add the rest of the advice required for your solution such as fumes, disposal, PPE etc etc.
If you believe that brick acid even comes close to a controlled buffered acid cleaner that took nearly 3 years to develop I feel sorry for you. Moreover you offer advice and knock products having never even tried them or compared them. At least I have tried and tested the alternatives you offer and know the results.
Kevin Martin
Tiling Logistics Ltd