Instead of water, you can mix the thin set (dry-set mortar) with this stuff, Mapei's Keralastic. "Premium-grade flexible mortar latex additive". I have many jugs left of this. (If you are not familiar with these additives, go read about them in Home Depot then buy it from me at half price!) $10 per 2 gallon jug.
I also have many 10 lbs bags of unsanded Mapei KeraColor U grout, # 39 Ivory. $10 each. (The sanded grout costs $17.74 plus tax at Lowe's and that is the cheaper stuff. If you need sanded grout, then you can just add sand to this and save money!!)
602~697~1877 (OK to call 07:00 AM - midnight. Hablo español.)
(I cancel each ad as the items sell. So, whatever is listed IS still available.)