Help with Den. Kingianum(not growing)

[sweta]

Hi Orchid Pals,

Need some help with Den.Kingianum. I've had this Den.Kingianum for close to 2 years now. I got it bareroot with a flower bud on ebay from someone. Since then the bud bloomed and shortly after there was another new psuedo bulb. After this I haven't seen any more growth from this plant. It did develop some roots but other than that nothing more. I have Den. Nobile which has been thriving but this one has been struggling. I wondered if it could be something to do with water as our tap water is more alkaline but from what I read up online. Dens like alkaline medium maybe thats why maybe Den. Nobile's been thriving. Its under grow lights in the winter and summer gets morning sun on window sill. Its potted in orchiata bark. I live in the pacific northwest, seattle area. Its fed with fertilizer weekly during summer and winters once every two weeks. I heard that den. kingianum is one of the easiest to grow but my experience has been otherwise what can I do to help it thrive and grow?