Question about Algae

[the new guy]

My tank has been up for about 6 months and all I have is brown algae. I am using 50/50 flo bulbs and was wondering why I don’t have any green algae? When I do water changes I use filtered seawater and when I do my top off's I use tap water. I know the tap water causes the brown algae but I only add about a qt every few days. Will the tap water prevent the green algae from growing?

 

[broomer5]

Most would agree that a little algae is good for the system, food source for your substrate critters and aids in having a biologically balanced tank. It sounds like you have the brown diatoms figured out.
Do you have any live rock or anything else in the tank that came from the ocean ?
Most true algae reproduce and spread/grow if their nutrient and lighting requirements are met - and normally some live rock will have more than enough starter cultures already growing.
Do you really want to encourage green algae growth ?

 

[the new guy]

I wouldnt say I want to promote it, I was beginning to feel like something was wrong with my set-up.???