Early growth problem. Appreciate any tips/solutions

[Prosper universal]

so I just noticed this issue with my new growth of leaves about four days before this post, I thought it was a nutrient imbalance possible PH problems due to my cheap pen malfunctioning. Im in coco perlite mix with GH nutes under DE HPS 6000K. I haven’t fed over 400ppm PH 5.5-5.8. Room temp is 52-75 F. 40% RH. Veg is at week 3-6 new growth is stunted, twisting and curled. some lower leaves are spotted with yellowish/white marks. I will include pictures. Thanks I appreciate any suggestions and tips related or not.

 

[Ezlyfe]

Buy new ph pen bluelabs makes a good one. Your temps are dropping too much for one thing. 50 degrees f is not overly conductive for growth and can affect root zone and ph with temp swing that drastic. Without decent gear to test ppm/ph ur dead in the water imo. Good luck getting it resolved

 

[Ezlyfe]

And one more thing I would look on the underside of every plant looking for bugs using 60x loop