Need help

I have 12-13 day old seedlings the second set of leaves look curled and deformed with whitish tips. My other seedling's leaves looks fine but has a whitish looking tip like the other. There is new growth everyday which look fine so far. Could this be some sort of nute lock I recently just switched from using tap and distilled mixture that had a ppm of 150 my starting off ppm was over 450.
I now use distilled water there has only been one watering with distilled so far. I'm hoping it fixes the issue but if someone can help me tell me what else I can do or what it could be I do ph my water.
I will post a picture
Thank you