
Struvite crystals are quite common in dogs, but only cause problems in a few. There's lots of info available if you google (such as
this and
this. A search will be confusing but ultimately worthwhile!
Boiling the water and cooling it would actually concentrate the chemicals, as only pure water would evaporate. The various bottled mineral waters contain different minerals depending on the rock they've permeated through - the purest water is distilled water, which is condensed steam.