why does this keep happening to me!!!

i just transplanted all was going well until now. Three days after transplanting. The same problem i,ve had with my last two grows.
The leaves first started to show small yellow spots only the older ones but then they started to go a bit lighter in colour they were pretty dark green and growing well but now the leaf tips are showing a little yellow now too on all leaves.The ph is at 6.2. growing in coco and potting soil. using tap water that has been left to stand a couple of days.
if its a calcium or magnesium def will epsom salts cure it. ?I havent used any nutes yet either but the soil was already fertilised and i had no problems until this week second week of veg.can you help me out pppppllllleeeeaaasssseeee

post some pics, easier to tell what's going on with pics

I hope you're not using Miracle Grow soil.

Don't use soil with added nutes in it. I bet that is where your problem is starting. I always stick to plain soil with no added nutes that way I know exactly what my plants are getting.

The added nutes are probably a little too strong for your babies.

sry no camera. why were they ok up till now if its the soil
and i had a great grow before with this soil it seedling and potting soil and no its not miracle grow