That looks like eriocaulon setaceum. I agree geleen, an extremely hard plant to grow, needs a lot of lighting, CO2 and nutrient rich substrate or it won't do well. Beautiful plant though, good job.
probably better off putting the diffuser by the intake not the out put. if you put it by the intake the co2 gets sucked up into the filter and diffuses in the filter and you have co2 rich water. it's a waste to put it by the output its no different than letting it just rise to the surface of the water.
CO2 has nothing to do with beard algae. If the algae is green and stringy it means that you have too much nutrience in your water. for example your iron levels are too high or your using well water. If its black brush algae, you are high in phosphates. so too many rotting plants etc.
If you dump the sand into a tank full of water its gonna cloud up. if you leave the filter running it should clear up in a day or two. if you pour the sand into the tank first and pour water into it slowly there should be no problem. That's with almost any gravel...especially the geosystem stuff.