How far to keep QB from tops of seedlings at 150w ...

getting new lights is always like..... how far the lights away from the seeedlings. Normally light companies give recommendations. as iam growing with similar lights ( quantum boards), i agree to you if you say, its tricky. And i would do it like... less is more until you found the right distance. I would start with around 80 cm and look how the lil ones respond. Or you dimm down to 30 watt, then you can go to around 15-20 cm.Its a great tool to dimm the lights. And the seedlings need a quite "weak" light. I most time use my secret jardin led ( each has 26 watt) to rise the little ones. In my Previous grow iam having same problem like you, i have new lights and dont know the accurate distance for the little ones.. So i start with 1 meter distance ( i got 150 watt Quantum board).... and then i look how they grow. if they get to leggy i lower the lights by 10 cm. iam guessing for 65-70 cm would be the optimal distance for my Girls in seedlingsstage. If they are 3 week old i go with the recommended distance from the lightcompany.