LOL, is that first picture what you are calling an outbreak? That is no outbreak. All tanks will get some algae. A little dusting here and there, some strands of GHA. No tank is perfectly rid of it. A new tank like yours will have rocks change all sorts of colors, from algae and diatoms etc. I would suggest you do not freak out, and keep doing what you are doing, which seems adequate. The only critique I'd make would be 4 fish within a month in a 29 gallon tank is aggressively stocking it.
BTW, this is a GHA outbreak:
