Detritus/brown algae explosion, help
 

Alright so I haven't been at this for very long so I figured I'd hit up the experts for help
The tank is 125 gallons roughly 180 lbs of live rock 3 anemone 2 pulsating Xenia, a very large colt coral , mushroom, 4 rock anemone and a few new LPS that I just added
Fish are a clown sweetlips, false perc, black oscilaris, coral beauty, manderin goby, couple starfish, hawaiian lobster, watchman goby and a regal tang and than around 3-4 dozen hermits and snails
Sump is a 90 gallon custom running filter socks and a psk300 with a uv sterilizer
Recently just upgraded the lighting to 3 250watt mh with 8 actnic t5
The water is testing good only thing showing is about 5ppm nitrate but my issue is what I'm assuming is detritus forming on the substrate and a brown algae starting to cover my rocks, seeing a huge explosion since I changed my lights, any advice or recommendations would be appreciated
Right now the only thing I can think to do is manually clean it when I do my water change and putting some mangrove plants in my sump to eat up extra nutrients
Thanks

Come over to the store and grab some cheato from me its free and will absorb more nutrients then mangroves do. What are you doing for phosphate export and what kind of skimmer you using?:)

Any pics of the algae? Also, how old is your tank? Are the lamps in the fixture new or used? Finally, what are your phosphate levels at?

It may just be a diatom bloom, which is generally an easy fix. Diatoms will spread too much and eventually kill themselves off. Turbo snails are great for controlling diatoms as well. Also research dinoflagllates. Hopefully, it is not that because they are terribly hard to remove from the system.

I would run some GFO (just be sure to add it gradually) if you are not all ready doing that and wait it out as it will get better, if it is diatoms.

Gotta be more specific which store cuz I think I know who it is just not 100 percent and I'm running a eshopp psk 300 it seems to be working really well

Also I tried to post pics it's just not letting me at this time my phosphate levels aren't even showing on the scale the only thing I have is the nitrates at 5 ppm
The tanks been cycled for about 6 months now give it take and seems very healthy
The algae almost looks like hair algae but it's brown and I know the on the substrate it's detritus cuz the wife was over feeding I'm guessing this all stems from that

It's very likely that what phosphate you are producing is being consumed by the algae as fast as it's being made. Also, one trick I've heard of is heating your sample water to 80 degrees celsius and then testing again as that often gives a more realistic measure of your phosphate levels.

As for the pics, try setting up a photobucket account at http://www.photobucket.com. It's pretty easy to upload there, and once the photos are on photobucket you can just post links to the image in the forums which will make them display in the body of your post rather than as links that people have to sign in to view.

Ill definitely setup the photobucket when I get a chance later on tonight and I wouldn't doubt the phosphates being burned up by the algae , even the green and coralline has boomed since installing the new lights I just don't wanna lose that ground gained by losing it to this brown fuzzy crap

Not sure if that worked the right way but ill try and figure it out later I guess

How long are your lights on for? What type of lighting are you using?