Whoooa there... is that water in that glass?!?!?! Chug that water out! Tryin to drown your little baby?
When using sprout cubes, add water from the upper surface of the cube. I'd say 1-2 bottle caps (regular coca-cola bottle size) per day. Keep a dripping pan under the cube. If there's a lot accumulating in the pan, add less water.
Get rid of the glass... glass, although not evident, absorbs and reflects light. In your case, that's not efficient.
79F is a bit hot, try reducing to 75-76F. If you can't, just keep under 80F. Your humidity is a bit low for a seedling, try misting some water (not directly on the leaves or sprouting cube, but next to them) or simply lay a bowl with water around there.
What soil you gonna be using? What strain is that? What are your night time temps?
Keep us posted.