Zebrina is growing too tall?

I have wanted a zebrina forever and decided to buy a corm last fall as a winter grow project. I had it in my grow tent for the first few months and it grew great in moss. When it reached about 4-5" tall I moved it to LECA and an east faving window with supplemental light 8 hours a day. It constantly pushing (and losing) a leaf, each taller than the last. It's now almost 12 inches from LECA to the tallest leaf. It's only been fertilized once since being in semi-hydroponics.... it it too tall?