What is this?

I had a batch of diatoms in my 20g nano recently, which showed as usual...right after the cycle. My CUC has done a great job at "pruning" it away as it exhausts the silicates. There was some on the walls of the glass and in the overflow box too. Now it looks like some are "sprouting" and a feathery like algae is growing.

I tried to identify it and it looks like "bryopsis" I think. Here is a pic I took with my phone.

What should I do? It's on the walls of my tank and in the over flow box too.

I'm getting ready to change the lights (2 HO T5's), as I don't know how old they were, b/c I got the whole set-up used and started from scratch.

Help...please?

 

I had that in both my tanks after cycling, and in both tanks it just disappeared after a few weeks. I'm not really sure what it was!