Distance of lamp

Hey, simply monitor the length of the stem, if it is getting too leggy your lamp is too far / too weak, if the stem grows slowly and the leaves are getting bigger you are in a good position. Just take 2 pics every day from a similar position, one above and one from the side. You will be able to tell from your feeling, but generally small seedlings dont need a lot of light during the first week / 10 days and your distance should be fine with this lamp. Good luck!

You bought it second hand ? Otherwise in packaging you have distancies. I was keeping 50 cm for youngs, 40 for veg and 30-35 for flower.