why so much algea?

[tony45power]

i have 200 gallon tank with 90 gallon sump. i have 4 small fish. i had an aggresive setup but i got rid of all my fish now im just starting to go reef. i just got a new light fixture its 6' long has 3x 150m/h and led lunar. i keep it on 6 hours a day but for the last week i have aalot of green algea on the bottom of my tank now. i have alot of water flow and the system has been cycled for over 3 years now. all my levels are good.

 

[Toddrtrex]

When you say "good" what are the actual numbers?

I am guessing that since the tank used to be an aggressive one that you were feeding a good amount. Going to take a while for all those excess nutrients to get out of your tank. Would suggest stepping up your water changes -- with RO/DI water.

All the new lights did was shine light ( pun intended ) on the excess nutrients in your tank.

 

[tony45power]

my nitrates just below 10pppm 0 ammonia nitrite good and ph good 1021 salinity. i have alot of algea in my refugium and now its starting to grow in the tank.

 

[dsn112]

Did you slowly acclimate the new light? If you increased your wattage and intensity, and never slowly acclimated your tank then thats probably your problem. Keep them off for a few days. Then slowly bring them back, using them only a few hours a day until you work your way up to where you want to be. You probably shocked your tank into an algae cycle.