I wonder how much reptile salesmen know about plants though.
The reason I asked about brown leaf tips is because that's often symptom of excess salt/s. Not necessarily definitive but it does suggest it's a possibility. Calcium in the water may actually be a good thing with coco fibre, which can be deficient and plants do need some, but I was pondering whether that could be contributing to the problem. Having said that, I have very hard (lots of calcium) water here and I'm not seeing salts on the surface of my houseplant soil, but then again they're in pots so have drainage whereas yours don't. In the field behind our house there are naturally occurring calcium salts on the soil surface of the poorly drained areas.
Since you're seeing brown leaf tips maybe I would replace the plantation soil with something else after all, since you can't flush it. Are there any garden stores nearby who could point you to something suitable that's available there?
