Yea, you can get fertilizers with calcium in them... Though, I would tend to think that the build up of that would not be particularly fantastic if you will. They do well with abundant light, and the ones at my local nursery are just sitting in a vanda basket. There is even a cultivar of one that has curly roots there. On the subject of water, I would be swayed to give them non municipal water on the fact they have to do all their photosynthesis, respiration, etc through roots. External buildup on the roots from tap water or whatever else seems like it would be particulary bad. I could be wrong, so no quoting.