Phalaenopsis stunted growth

[gul]

Hello, orchidboarders.
I have an orchid which I am not able to keep growing. It has been 4 years since I bought it. It was not in a very good condition when I bought it and my tendency to overwater caused further problems - root rotting. It had a few flowers when I bought it but it hasn't given any spikes or flowers since then. With the aim of triggering new growth I keep its roots in water in open air at the start of summer for a few weeks and then repot it and continue to keep it in the open air until the end of September. During the water treatment it grows new roots and last summer it even started a keiki. It continued to grow roots in the pot, too. After taking it indoors I saw some small flies around my orchid so I repotted and cleaned some small beginnings of rotting during the process. I got rid of flies but I suspect that some of the roots I had cleansed continued rotting inside the pot. The trouble is that there is no new growth in my orchid since I took it indoors. The keiki has been staying almost as it is for months now and there is no new leaf or spike formation. I manage to get it growing new roots and leaves in spring- summer through water treatment but throughout winter the growth stops. Have you got any recommendations about how to get this orchid growing?