Is this enough light?

My lighting is 120 VAC 60Hz and 20W is this T5?  how many bulbs. P.S If this light is not strong enough I will get a new light. Also I was looking at the Ricordea coral and noticed it needs low light needs moderate to high, but what about at nighttime when you turn the light out coral are fine right yes? Also when adding Iodine and the trace elements, are you testing for this? do I have to rmvoe the carbon from the filter should only run of and on (like ever other week)? Iodine and trace elements are the only 2 hings I would have to add to the water correct..only if you are below the normal levels  for this particular coral?

my new light is a T8 and it is a 50/50. 17watts. Is this a strong light? It is one bulb. No i'm not testing for iodine and trace elements. I don't understamd what you said about the carbon

 

So if it says this coral will benefit from certain supplements I shouldn't add it because I do not test for it no, you should get that test kit so you know if there is enough of it for that coral to flourish? Some corals I would like are Ricordea mushroom low to moderate light, Trumpet coral moderate light, Fox coral low to moderate light , Branching flowerpot coral please do not get one of these, they will die in 6 months (should be left in the ocean) . My filter comes with carbon in it, so if I just dump the carbon out and let it run like that yes unless you don't have any other type of filtration, sump, wet/dry? I won;t have to add anything to the water maybe depends on test? I have a small reef with LPS do 10% water changes every two weeks, once in awhile I add PH buffer.