I'm no expert but I believe Sativas grow to be quite tall... MUCH taller than Indicas. Also, your plant will stretch a lot if you have the light too far away. I think it might have more to do with genetics like bb007 said, rather than your lights but I don't have a lot of information or knowledge to diagnose this properly
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How big is your grow closet? a normal closet that's taller than you? or a special closet for a stealth grow that's quite small?