Not sure if anyone still here, but I just got two really beautiful Alocasias and I want to brag a bit ;)
The one with dark, shiny leaves is Alocasia Cuprea, and the one with pretty stems is Alocasia Zebrina. I do hope they like their new home - had a bit of mixed luck with Alocasias in the past...
Straight from a store, and they were watering them with tap water, that's what I do too. Fortunately I live in Tokyo, so tap water is pretty high quality here :)
Some time ago I bought a very small Cuprea myself and almost lost it. I found it difficult to keep the soil continuously not too moist, but not too dry either. When there was no leaf left, I repotted it in a Lechuza planter (a combination of baked clay granules, water reservoir and self-watering wick) and it recovered. I guess that keeps the right balance and avoids root rot.