Ok let’s do this: let’s find your light sweet spot. Let’s move it closer over the period of a few days to a week. With your lights I would start at around 15”.
Move lower about .5 inch a day until you see one of three things.
The plant “praying” to the light upturned leaves. This is usually the first sign.
Leaf edge curling up.
Or yellowing top leaves.
Any of that happens back it off an inch. Then measure and try to keep your light that far from the top of your plant throughout your whole grow.
More info here:
https://www.google.com/amp/s/www.growweedeasy.com/cannabis-light-burn%3famp
Also if you can afford it consider adding more light. Though take into consideration your exhaust. Can it handle more heat or will it need to be upgraded too?
This is a much better light than your blurples and in the same price range.
https://www.amazon.com/Quantum-Board-Grow-Bloom-4000K/dp/B076QDKVDZ/ref=mp_s_a_1_7?ie=UTF8&qid=1548035809&sr=8-7&pi=AC_SX236_SY340_QL65&keywords=quantum+board+led&dpPl=1&dpID=4155OYwc2cL&ref=plSrch
Use this and your current lights together. To a certain point more lights is better.
Happy growing bro.