I think a lot of people use distilled water, which isn't that different from pure rain water in theory, without any issues. The big issue there is hassle and cost.

When I used to keep aquariums, I would use dechlor products to condition the water. Go to a fish or pet store and browse around. At the link is the product I used to use. I'm guessing it's safe for plants too, but not 100% sure.

Here is a link that might be useful: Dechlor Product

Yeah, my big concern with using a dechlorination additive would be that one of my plants seems to be very salt sensitive so increasing solutes may do more harm than good.

My least healthy plant is a Melicoccus bijugatus (I call it a mamon). It seems to lose leaves at about the rate that it grows new ones. The leaves come out looking perfectly normal then over the course of a month or so will develop these small crusty looking spots that do not wipe off. The leaf will begin to yellow (light spots are starting to develop in the photo) them dry up and drop off. Here is photo with the crusty spots and the beginning of the discoloration... Thoughts anyone? So far using evaporated water may be helping, but it is too soon to tell (and I'm sure there is still a reasonable amount of chloramine left).

{{gwi:52117}}

This post was edited by sf_rhino on Wed, Oct 9, 13 at 0:08

Is it possible that you are overwatering this plant? Your photo reminds me of some I've seen in the Tomato Forum of edema in tomato leaves caused by overwatering.

Here is a link that might be useful: Physiological disorders of tropical foliage plants

I posted this photo in the Pests & Diseases forum as well and I am also now starting to lean toward edema.

I am not entirely sure how to fix the issue, as I have to keep the soil fairly wet in order to keep the plant from dropping leaves. I guess I'll try methods of increasing the transpiration rate. Maybe give it a good root prune and try another medium.
The plant currently gets no fertilizer. I would like trying to give it something, although when I've given it even the smallest amount of FP it drops its leaves. Perhaps an organic fert or a foliar application of some sort would be good here? Any suggestions? I am hesitant to give any liquid ferts right now b/c it would likely just increase the water uptake and compound the edema (if that is the issue).
Thanks!
r

Here is a link that might be useful: discussion in Pests & Diseases forum