Please help me with my phalaenopsis orchid problems about their leaves

[danliz]

Hi everyone,
I am newbie to the forum as well as to orchid. I have no idea what is going on with my orchids.

I just bought two orchids, and here are the problems. There are black stuffs like dust at the base of the orchids. What are they? Are they fungus? One orchid has yellow spots on its leaves (white phalaenopsis). It is too much water or too much sun exposure? Another one has black spots which damage to the leaves (purple phalaenopsis), and back of one of its leaves are purple . It is fungus attack or sun burn? Is it because the leaves received too much sun that it turn red tint or purple? Both orchids don't have healthy root systems or leaves. Their leaves are long and drooping. Why? Is it because of lack of sun? water?....

I also have problem with long leaves and drooping with my denbrobrium which I also attach. Why does this happen?

I also attach another picture which is my seeding orchid. Its leaves are purple too, don't you think so? and why is that? All other orchids have this problem, and the leaves seem want to die out (yellow) without growing new leaf or root.

I do cover them with the hard plastic. The height is about 1m. They don't receive direct sun or morning sun. They can enjoy a bit of afternoon sun.

I live in Indonesia so the weather is pretty hot, and I don't even know when is the raining season or hot season since I just moved here.

Thank you so much for your help in advance.