First off, welcome.
That light is very intense for cloning. Even a single small flourescent is plenty!
I suspect that given SO much light, it's tryin gto grow leaves, and in absence of nitrogen, it's using up stored N in the leaves.
I'm not sure about the application of hygrozyme in cloning.
What did you use for rooting hormone?
Anyway... decrease light intensity and see if it slows down.