This being my second try at seeds is really frustrating. The biggest learning curve for me is lighting. Different height suggestions of light. Different intensities. I know this is how the internet works but that doesn't make it less frustrating. My current grow is at least 3 to 4 weeks old. I was told to have my 450 watt light 32" above at intensity level 3 or 4. I think my soil has to much drainage to. Can anything be done with these? There stretched further than my bank account.
You can buy a light meter that reads par but they are expensive
If your a math guy you can get a free app that reads lux and convert that to par however that will only give you a idea you still need to use your eye.
24-36” is the right recommendation depending on age and height.
Sounds like someone’s taken veg height and applied it to seedlings.
We don’t run leds at max because there to intense and burn the plants hence being told to dim it. That parts right.
I know the information on the net can get very confusing and contradictory.
I just re read they are three weeks old your definitely overwatering they should starting veg growth, there tiny for three weeks bud they still look a week old seedlings let them dry and good luck
Good luck