Critical O P grow

This week is a strange one. Germination went great, soaked for 18 hrs in room temp tap water then transferred to wet paper towel for 48 hrs. Nice one inch taproot so planted in coco and watered with dechlorinated tap water ph'd to 5.9. Seedling sprouted in 36 hrs but I was I was waiting for a new light delivery so had to leave in the dark for 10hrs. Got home and she was standing tall about 3/4 inch high with her cotyledons still closed. Now, She is sitting under a brand new 2ft maxibright T5 with 2, 24 watt bulbs that give out 3300 lumens. Yet she won't stop stretching? Started the light at 12 inches as per recommendations, checked the following morning after 11 hrs and she had gone up another cm so dropped the light to 6 inches and left for 24 hrs. Still stretching when I checked this morning so dropped the light to 3 Inches from canopy. Hoping that's gonna stop the stretch. Also on day 2 (early I know) She got fed some roots and start from Shogun. Seems to have liked that.