Hi LovePhals,
Vandas get potted in same mix I use for all my orchids i.e.
1. Composted pine bark 10 to 20mm size (1/2" to 1" size pieces) 60 to 70% of mix.
2. 10% course River sand .
3. Polystyrene (course granules, from recycled white goods packing).
Plants that like good aeration I put more polystyrene & plants like slipper orchids I use less polystyrene.
I feed with a '8 to 9 month' slow release fertiliser called Osmocote "Exact" which has trace elements in it. As I am too lazy to liquid feed my plants .
I do not feed orchids with this fertiliser which need a rest period like soft cane Dendrobiums, as this fertiliser will result in growth not flowers. I make an exception by liquid feeding these orchids.
I find Vanda orchids one of the easiest orchids to flower in my climate (similar climate to Sandiego in the US).
The following images show some of my vanda collection including the red vanda (in flower for second time), sitting in a small glass house (with out heating) to prevent frost damage.
Images taken today almost middle of winter.