I would if I were you. You have two things going against you. First, mastic shouldn't be used in a wet area. The reason is that even after it's been dry for years, it can still reimulsify (become soft) from contact with moisture. Secondly, even in dry areas where mastic CAN be used, it's not supposed to be used for anything bigger than 8x8 tile. The reason for that is that if you apply mastic too heavily (as you would need to with the larger tiles-- anything bigger than 1/4x1/4 is too big for mastic) then it won't dry, and if you use a 1/4x1/4 notch then you're not getting the coverage you need to have. So now, either you don't have enough adhesive behind the tile, or it's going to stay soft, which means it'll wash out from behind the tiles all that much quicker. Take the tiles down.

All the BBB people will disagree with this so do me a favor and don't reply with 20 reasons to the contrary. I somewhat agree with the BBB approach but it is not an end all. If you are a straight chlorine buyer (not grocery store bleach), you are screwing yourself buying from a hardware store or big box retailer. The general rule is if you juice comes in a box, it's a waste of money. On strength the kill, it loses most of that in warehousing. A bottle at 12.5% is way weaker than that by the time you see it. but, you are paying for 12.5%. I'm guessing that is why the BBB folks prefer clorox as that is about what you get so why not pay clorox pricing. Makes sense to me. Anyway, your local pool store has a supply that arrive from the chem plant weekly so it is considered fairly "hot". Literally, put clorox on your hand and then put a fresh dose of good chlorine. It's hot. The pool guy, the pool store, etc have access to chlorine that is about a week from the plant. It's fairly close to 12%. That means more killing power per dose and you use less. Count the cost for less product and more money or less money and more product and it's about even. I only bring this up to show that the local purchase of pool chlorine is not a ripoff as long as your are buying it in returnable cases. Cardboard box is another story as it sells slower and sits. Soda ash is a ripoff. You can buy a 50# bag whole sale for $18 or a 5# can wholesale for $9. You are better with a purchase of 50# of baking soda from Costco. The end result is a pH much closer to what you want.

I suppose they are all created equal. But I have 2 and one works better than the other. I don't know what brand it is though. If I were looking at them in person, then I'd get the one that has better 'teeth'...that seems to be the difference in mine. Other than that, I'm afraid I can't be of much help.

OK zkathy - here's the list of names in alpha order - but it's a little obvious in some of the photos already - you can see the labelled painted rocks! Good luck with your guesses. America Hero Atlantis Blue Mouse Ears Choo Choo Train Cutting Edge Diamond Tiara El Nino Fire and Ice Flemish Sky Gold Standard Great Expectations Hadspen Samphire Halcyon Hi Ho Silver Janet Liberty London Fog Luna Moth Marilyn Monroe Orange Marmalade Pineapple Upside Down Cake Queen of the Seas Ripple Effect Summer Breeze Summer Squall Sun Power Touch of Class Trifecta