Lighting concern

[Joshifer]

So I was using an aquaneat simple led light on my 5G. My hammer loved it. Today the thing sparked and blew up Idk I guess cus it’s too old. Bought it 2nd hand.  Most of the leds were going out anyway. 
 

my concern is; My tank won’t be in complete darkness during the day. Light comes in the room. It doesn’t get direct sunlight. But some light. I ordered a new light it won’t be here til Tuesday and it doesn’t have a dimmer or anything just on off or blues only. Am I gonna put that hammer coral into shock by turning it on full power? lol it’s a small tank I don’t have much room to play with when it comes to redirecting lights. And I’m not sure if a lamp dimmer from walmart/Home Depot will work on it.