Is it normal to get green algae on LR?

[spankey]

I have a 20 gallon nano. I have 15lbs of Live Rock some zoos and some xenia... It houses 2 yellow tailed damsels and one red lipped blenny.. About 5 hermits and 2 snails and one peppermint shrimp...

The lighting over the tank is 100 watts of 6500k PC.
One 10,000k 9 watt bulb and 1 9 watt acintic bulb... Roughly 6 watts per gallon of PC lighting..

I leave the lights on a timer for about 7 hours a day.. The zoos and xenia are thriving... I also have some tube coral that I see popping out from time to time...

My test parameters are perfect... Nitrites and nitrates are 0. My ammonia is 0 and my phosphates are 0...

I use RO water for water changes and such...I am running a skimmer as well...

My dilema or question is this?? I am getting green algae on the live rock? I am getting brown algae on the glass.. I scrape that from time to time.. Now mind you the green algae is a real bright green alage... Its not an ugly color.. But is this normal? And will this diminish???? I just don't understand because my tank parameters are perfect?

Can anyone else explain this and is this normal??? I cut two of the 19watt 6500k bulbs off to see if maybee its getting TOO much light???

Again, can anyone help me out here??? I am picking my brain???

Thanks
Spankey

[mogurnda]

Is it hair algae or coralline? Green corallines will often do well in brightly lit areas.

[spankey]

Not sure, it doesn't look hairy.. Just looks smooth like? Maybee this weekend I can snap a picture of it.. I am working nutty hours right now...

Spank