



Mosaic tile pond progress and question
Been working on this shallow/ pond/fountain for the past few months. Still have to add the Mexican style water feature/fountain that will pour water into the pond. At this point I'm in the range of 60-70 hours of tiling work alone. Progress has slowed because it's now 109° and I'm on the verge of heat stroke.
My question is around grout. I planned to use epoxy grout only in the pump pit, at the lowest point, because it'll be underwater more than the rest of it (I also have some white epoxy left over from my shower project). That part is completely hidden with a large square drain cover. I don't plan to keep the pond filled with water and only use it when we're out around the pool or when we have friends over. My dogs like shallow, beach type water so they can play in it. It's also just too hot here in the summer and the water is going to be 140° because of the dark glossy finish and it being so shallow. I'd be fighting a never ending and never winning battle against algae. For the rest of it I planned to use Mapei Ultracolor Plus FA because
* I prefer the look of sanded grout
* It's cheaper
Is there a better sanded grout for underwater applications? I want to keep it as waterproof as possible though I do have like 5 coats of a liquid membrane covering the entire concrete base (concrete has steel mesh plus fiberglass strands to mitigate cracking.
Also what color do you think works best? My initial thought was a tan/sand color, possibly even in the haystack range. Main reason that it'll help with the transition from the pebbles to the regular Arizona dirt/gravel of the rest of the yard. At the beach entries I'm adding about 2 feet of concrete so I can embed larger river rocks and transition those to the pebbles, which transitions to the tile (all grouted).
My fear is that tan won't look good with the yellow. I've done a ton of talavera inside my house and always used regular Natural grey which seems to work with every color. The downside is it'll stick out at the beach transition area. I could sprinkle the grout, once it's applied, with decomposed granite so some of it sticks and helps with that area.
Sorry for the winded post. This project is borderline killing me and props to all the tile pros who do small tiles on the ground. My knees and back barely function anymore from being hunched over on my knees on a downward slope.