Vanda Growth Setback

[aussieboy]

I’ve purchased a vanda tricolor var. planilabris last fall and the orchid itself is not in good shape. It just have one long dormant root and most leaves are covered with black spots. I felt a bit rip-off on that purchase and vowed to never again buy from that seller.

Winters passed and is now spring here in Australia with temperature between 14 - 35C. All of my orchids are either in spike or resuming their growth except my tricolor. I tried watering it often and add seasol which probably is the local equivalent of kelpmax. But none of these seem to work. How can I get it to resume its growth?