I would guess and say by your photo that might be a tad bit close due to the age if seedlings ...back it off a bit ...but if it's working then great!!!
With a new bulb I have to have my 400w mh 48 inches away from seedlings that's a different light I know but ...
Cant go wrong with a bit higher and work your way down .
Always give some some time for the leaves to show their thing like 24hrs etc