Looks like the topical failed/degraded.
Strip off remaining topical
Then maybe a light acid dilution
I would test a small area as the face of tiles look like they could be damaged

Sent from my iPhone

> On Aug 23, 2018, at 11:08 AM, Tony Deluna <tndeluna@gmail.com> wrote:
>
> Hey pros what would you guys use to clean this quarry tile around the swimming pool?
>
>
> Visit list archives, subscribe, unsubscribe or change your subscription
> preferences:
> http://stoneandtilepros.simplelists.com/sccpartners
>
> Start a new conversation (thread):
> sccpartners@stoneandtilepros.simplelists.com
>
> <IMG_2747.jpg>
>
>
> Tony DeLuna
> 925-625-9625
> www.PatriotStoneRestoration.com