Brown Algae In Bottom Coral

Over the past two weeks, My tank is growing this Brown Algae around the bottom of the tank, and on the surface of the crushed coral. The tank is not in direct sunlight, and I am running the 50/50 lights for about 8 hours at night. I have 10 Hermits in the tank, as well as 3 turbo snails and 3 urchins. Can anyone please tell me how to control this algae? I heard that if I completely cover the tank for 24 hours+ and leave the lights off, that it will kill the algae. I rather not do this. Is there a chemical, that is "SAFE" to add to the tank, that would cure this problem? I have 4 fish in there as well. The fish are completely health and not showing signs of stress. I also have a few cleaner shrimp and a carpet anoneme. The Nitrate, Nitrite and PH levels are perfect!

Thanks In Advance.

About 4 Months Running

The tanks only been up for about 4 months now. Some of it is starting to turn green, on the rock,etc. I keep the glass cleaned and it doesn't appear to be harming the fish at all. They won't eat it, but it is not harming anything. Now I find last night, that my Nitrates have spiked tremendously. All other levels are perfect. I am doing a nice water change today, and will also clean some of the algae during that process.

Thanks for the input.