abnormal stem with nute burn or deficiency?

I'm growing a bubblelicious 2 week old seedling with the stems on the new groths exremely big while the lower node and stem is thin and can't support the plant. I have a 7 inch fan 4200 lumen floro and a 2600 lumen floro to acompany it I have been giving it tap water at 6.4 ph but plant is limp but slowely growing any advice would be great

how many watts are your lights and how close are they to the plant....normally if the plant is tall with skinny stems then they are not getting enough light....and is that fan blowing around them or right on the plant?

One of the lights is 42 and the other is 68 I live in a relatively sunny area so I only have it in on cloudy days and night but it seems if the stem and petiole get skinny and limps on the first node but on the second the petiole is as fat as the base of the stem or bigger and full of life just that first node after the waterleafs skinny stem can't support the healthy top