I have Quartz-Lock grout (first generation, not the second generation QuartzLock2) in my kitchen floor. "Mushroom" color. For the first 12 - 18 months it looked great. However, in the last 6 months or so, it's started to look very very dirty!

What's the best way to clean it? On the QuartzLock website it says that enzyme-based cleaners will damage epoxy grout and void warranties...is Oxyclean an enzyme-base cleaner?

Here's what the website says:
Alert/Caution

The tile industryÂs customer base has struggled with effective cleaning protocols in commercial environments for years. Different types of cleaning chemicals have been used to some degree with varying performance benefits.

In tile installations today, we are finding an increased usage of enzymatic cleaners in replacement of more traditional cleaning regimens. These cleaners can have a severely destructive effect on epoxy, urethane and latex-containing cement grouts.

Since the full effects of these enzymatic cleaners are unknown, many job failures have been reported. We are recommending that your customers continue to use traditional cleaning methods to avoid potential job failures.

At this time, we are NOT recommending the use of any enzymatic cleaners for QuartzLock Grout and will not warrant any installation using these enzymatic cleaners moving forward.

They seem to recommend bleach or toilet bowl cleaner.
For calcium, lime, or other water minerals...For stubborn stains use some type of toilet bowel cleaner or a lime and calcium deposit remover.

For stubborn stains (tomato paste, wine, etc.)...We recommend using typical household cleaning products like Soft Scrub with Bleach Cleaner and any available citrus cleaner. Do not use Enzymatic cleaners, as this will void all warrantees[sp].

Thoughts and comments?