Is this caused by water quality?

[Wrebbitrocks]

hi, i have 3 besseaes in my collection and i have 2 of them potted in spagh and one in bark. 2 of the plants(one bark one spagh) started getting dark tips and dying back rapidly. that was when i watered them with tap water once a week. i panicked and cut off the brown areas and it continued up the leaf so i opened a couple bottles of water and ran watered them in it and left them standing in the water. the dieback stopped and after reading that phrags are picky about water ive left them standing in bottled water.

so was the dieback caused by the tap water? the 3rd plant seemed fine and was actually just getting bigger and wasnt affected. the other tw lost a couple growths rapidly but are now recovering with new growths after using bottled water. heres a picture of the plants before the dieback and after dieback on 2 plants.