Jamie, do you uses bona pro3. I found that the best on floors that can't be cleaned. We had a university swimming pool where 7 other companies had been in and could not touch the dirt / congield skin. I tried Bona main, clean, 1,2 and Decon, but only pro 3, used at neat cleaned it. It came up amazing thou. But got 40 litres of the stuff sat around now left over from the job.