vanda root problem

[flytrap7108]

hi i have a vanda and it has been doing very well for 2 months infact it is now in spike. But the problem is no matter how many times i water it the roots seem to stop growing and the green tips are shrinking. i have it in an inclosed system with about 70% humidity and above and the temp is very hot. it is about 90 degrees so i think im doing everything right. i water it once or twice a day and i dunk the whole plant in a bucket of water for about 30 min or so and take out. The plant is in a plastic basket with the roots hanging down so i just cant find the problem. the roots are looseing there green tips this is bad. I was just wondering if anyone has had this problem before or nos whats wrong.