Hello ZH, what you read about watering is correct, they do not need to be watered everyday. Your area also has high humid heat year round. At the very least those blooms will last from 2 weeks to a month. It is in its natural end phase of the blooming cycle. What is important now is to help the plant continue on growing after the blooming period.
The media it is in, is okay, that is quite typical being used in Asia, to accommodate excessive moisture levels there and if grown outdoors the frequent rains. Your plant is still in the adjustment stage as already mentioned, so it is understandable it will drop some blooms faster than usual. Later on, that plant will try to grow aerial roots, so just let it be, Dens like their roots like that, with lots of air access. It may also either try to do basal keikis or it may do keikis anywhere near the top of the plant. When that happens, just allow the plant to grow those babies at the top till it reaches half size of mother plant, and then you can gently twist it off and plant later in its own orchid media.
I remember before in my homeland, they grow orchids on coconut shells and husks and they add some charcoal too. So easy to grow them there, they like the warm humid weather.