Heeeelp! sick orchids

[Miamiheat]

Hello,
I have 4 or 5 orchids exhibiting the same type of problem. New leaf seems to turn mushy and yellow with some brown spots. Lost an orchids to this last week but didnt really worry as it has no roots and looked terrible to begin with. One plant had 2 basal keikis and it seems both the plant and keikis are showing the same problem.

First i need help identifying what it is: fungus? crown rot?

Secondly what can I do about it? Please keep in mind i live in Dublin Ireland so brand names of US or other non European products wont help much as we don't have the same products. Natural remedies or actual chemical components will be better.

thank you very much