YOU CAN SCRUB FOR HOURS OR FOR 15 MINUTES - YOU CHOOSE
This floor - The floor only took me personally 15 minutes ... WHY?
I allowed SHYN degreaser to sit on the floor and marinate for 15 minutes I had the shower running with water flowing down the walls and onto the floor. Using my grout brush, i brushed out all the grime in the crevices I used a drain brush to clean to get into drain cover holes and gave it brush. I used my double strength magic eraser to remove any fine soap scum, there was nothing really to come off just a real little bit.I tell you this because it wasn't just one thing i did, it was the system i followed, everything works together to get us the results we achieve 
Think about that next time you embark on a tough job, what tools do you need to get the job done in the most efficient and effective way and how long are you going to take 
Ps don't rush you'll hate it, when you do