If it's Cyano do chemi clean works like a charm. There is no harm using it, if you use chemi clean and it happens to be Dino's it won't affect anything and then you know you have Dino's for sure

Should be a win win

That's not a bad idea. There could easily be a mix of dinos and cyano too.

If it does turn out to be dinos, H2O2 (hydrogen peroxide) dosing seems to be the strongest offense, and since you don't have many corals you don't have to worry much about irritating/browning the corals.

Thanks for the suggestions, i'll give the chemi clean a try first and see how it goes.

Yup just follow the directions good and shouldn't have any problems

I leave my skimmer running and just leave the plug undone sour flows back into the sump so you get lots of airation during the treatment

Personally I would run GFO less or stop for time being. I would also try to raise NO3 a little either by adding NO3 or feed more.

I think the problem is your PO4 >>> NO3, that's why you have cyno outbreak.

I had the same problem, then I read up on the Redfield ratio. Worked like a charm for me.

That looks like dinoflagellates. Once it takes hold of your tank, it is very challenging to get rid of. I had a nasty case of it that cost me a few corals and almost killed my gorgonian. I was able to get rid of it by doing a total tank blackout for 4 days along with daily water changes during the blackout and for 2 weeks after.

Update, since i have no corals left now i decided to do a full blackout for 7 days. No water changes during this period and reduced feeding amounts, the last 2 days(Aug 12) i also added chemi clean. On Sunday i turned the lights back on, the algae receded. On Monday i noticed that it already started to regrow, it looks similar to this:
http://i296.photobucket.com/albums/m...pskvrjuyjy.jpg

I also gave a sample to a friend yesterday to look under a microscope and he said it looks like Dino. So i guess my next step is now trying H202 during a blackout if that doesn't work look at using metro. I read Jennc comments but i have also read conflicting comments stating no water changes should be done during treatment.

I'm not familiar with the Redfield ratio, i'll have to read up on that. I did read that increasing No3 does play a role as well.

I didn't use any chemicals or special treatments while trying to rid my tank of dino. Having the tank blacked out and the water changes was all it took. Once I had it under control, I pulled all the equipment and thoroughly cleaned it and then replaced all the media. I do run a UV sterilizer, which probably helped as well. Good luck!

Bummer. Good luck. H2O2 usually takes awhile too.