At which concentration and at which frequency ?Thank you for all your kind comments everyone. I've had the plant for a few years. It was a division from a larger plant belonging to a very good paph grower in my orchid society. I've been growing it under T8's but it also gets some supplemental lighting from the skylight above my light stands. It has a 38 cm leaf span. I mostly fertilize with MSU/CalMag but sometimes rotate with a couple other fertilizers and I grow it in orchiata/perlite/charcoal in an opaque pot. With this blooming it's consistently had 2 blooms open at once and more recently 3 blooms.