Hi
@OneLeaf! Each LED manufacturer has its own recomendations about this. One of the best way to find the right distance is to do the universal "hand test". If by placing your hand on top of your plant's summits, you get hot / your hand burns, then this distance needs to be increased. Later, your plant will spread and you might need to increase this distance for better coverage. If you don't notice heat (hand-test) nor light-stress (weird colors on leaves) then you're good to go with your current plant<--->light distance. Hope this will help, keep us up-to-date and happy growing 👊