I agree, it is a little hard to tell from that picture, even though it is a pretty good closeup. Some questions that might make it easier to identify: Do the strands branch at all, or is it just single long strands? What is the texture like -- Is it stiff, coarse, soft, slimy, etc?
I could be wrong, but I don't think it's hair algae. I usually don't see hair algae growing close to the substrate like that (unless it's in a tangled mass -- just like tangled hair), and from the picture it looks like it's more coarse. Hair algae usually is usually very thin, long strands.
If it's what I think it is (more coarse/stiff, some branching strands), then I've seen it described as horse hair algae and sometimes even staghorn algae (although I'm pretty sure those are different things). The closest I've come to identifying mine is Pithophora. Whatever mine is, my shrimp completely ignore it.
Speaking of shrimp, what kind of shrimp do you have in there? Some are more tolerant of different algae treatments.
It grows in clumps and only close to the ground. My CRS completely ignore it. Its not slimy and I dont really see it branching out. It just grows in clumps. I tried to over dose with excel but that didnt work. Black out for 3 days and that didnt even phase it.
What else do I need to do. Its going to take over my ground cover!.
With all due respect to chagovatoloco, if your plants are doing well, I wouldn't go and change your fert routine (whatever it is or isn't) just yet.
Well ... I was writing something that was getting rather long, so here's the condensed version: I've had algae that sounds and looks similar to what you've described. Any time I changed my fert routine (for the "better"), that algae really took off. I've completely eradicated it in two (hopefully 3) tanks now, but my methods for complete eradication are extreme. If you get REALLY REALLY frustrated, and you've tried everything else, feel free to ask me about the "extreme" method.
(the non-extreme method) What I would suggest is to turn off your filter and try to remove all of that algae you can manually. Be very careful not to let small pieces float away, because from what I understand, this algae reproduces mostly by fragmentation, so any floating pieces can end up starting a new infestation. After you do that, you should spot treat (with a syringe or pipette) the areas that still have some of it (like any that's on plants, or attached to gravel) with a small amount of Excel. If your shrimp haven't had any problems with the Excel already, you should be safe using up to the amount that you'd be dosing to the entire tank -- just don't use more than that. You might actually want to feed your shrimp away from the area you'll be treating to try to keep them away from the concentrated Excel too. Leave the filter off for 5-10 minutes after you've done this. Repeat the process the next day, and see how things are going.
Yesterday I tested Excel spot treatments on my two tanks that have similar algaes (they may even be two different types). In one tank, I had previously been overdosing excel just into the water column (not directly on the algae), but it was having no effect. With the same amount of Excel put directly on the algae mass, it has already gotten really soft, and is now yellow instead of green. In the other tank (the one with shrimp), the algae still looks the same, but I've noticed that the shrimp were on it trying to eat it now. Maybe they can sense that it's dying and it's more appealing to them. I'm going to do another spot treatment today, and I'll let you know how that goes.
If the excel doesn't work for you, another option is hydrogen peroxide spot treatments. I've read somewhere on here that certain shrimp are very sensitive to it though, so it would have to be in really small amounts.