25cm, that is nearly 11 inches in 8 days.
More than an inch per day.

That is astonishing growth for little seedlings barely a week old.
Are these clones?
JohnnyPotGrower Reviewed by JohnnyPotGrower on . 6x PowerPlant on soil (1200W) I just started out again with 12 PP in my cabinette. I´ll make my choice of 6 of them that I´ll bloom. I won´t give them any nutrient during VEG with the exception of root nutrient and mycorhizza fungi. They´re in VEG for 3 days now. I´ll have a 2 week VEG. Rating: 5