Brown Hair Algae

[geosquid]

Scrubber is growing a type of brown hair algae.

My scrubber has been up and running for about 2.5 months..give or take. The first few cleanings I was getting a nice green hair algae but not it just looks mostly brown and doesn't grow as well. Some background.....currently, the set up is a 250 g/h pump pushing water up about a foot above the tank to horizontal ATS 3"wide X 27" long tilted at maybe 20 degrees or so. Above it is a 39w T5HO 4100k bulb. The water flows over the horizontal ATS and down to another trey reservoir above the tank and then overflows to a one sided vertical ATS 18" wide X 4" down lit by 14000k metal halide and this flows right into the tank. The tank is 47 gallons.
I know the bulb is getting close to three months old but I just don't think that is the issue. the horizontal ATS grows green hair algae mostly on the sides but the main raceway has mostly brown algae. Its not the tar looking algae either its more of a hairy algae. Is my flow not enough?
Originally, I made my ATS more like the santa monica version - two sided vertical 3"x30". I started using 750 g/h flow to make it work but nothing I tried would get rid of the micro bubbles in the tank. I cut the flow down to 500 g/h and still had the same micro bubbles. I tried all the micro bubble fixes outlined here but nothing worked to my satisfaction. I spent $60 in PVC on a number of configurations but I didn't want pipes all over the inside of my tank so I came up the configuration above.
I had the one sided vertical ATS 18" wide X 4" lit by MH bulb for some time before I install the horizontal ATS. The vertical was growing some great GHA even with the MH bulb. Once the vertical was up and running and growing GHA the horizontal started growing much slower. Now, the vertical is almost all brown algae and the growth is very minimal. The Horizontal is mostly brown with green on the sides of the flow and I'm getting about half the volume of algae when I scrape as I was the first three or four time I scarped it. The flow in the horizontal seems pretty good and makes some good rapids down the middle.

Any info would be grateful.

[SantaMonica]

Horizontals block flow as they grow; you have to have tons of flow to get up and over 3/4" and 1'" thick growths. So yes you need more flow.

Your lack of growth might be from less nutrients in your system. How is your nuisance algae?

[geosquid]

I have absolutely no green hair algae in display but I still have to clean the glass every two days. The stuff on the glass is not green, its more of a powdery white. I do have these little brown singular like hair things growing on the back glass very sparse - its one hair by itself not a clump. When I was growing good green algae on the filter it looked like flow was starting to get a little blocked but it usually didn't happen until around the time it was ready clean. Now, the flow seems great right down the main channel but its brown. The GHA only grows along the sides where the flow seems less. I feed the fish about 4 cubes of food and another cube of coral food that I make from oysters. I also have some Macro algae in the display that has seemed to stop growing also. I don't have N or P test kits so it may nutrient limited but that just seems odd for how many fish and how much I feed. I know it no where near as much food as the ocean gets but the fish are fat. I was thinking of trying more flow but had so much trouble with micro bubbles in the past and so many different configurations with pvc.

[SantaMonica]

It's not growing in the middle of the trough because the light is too strong for how much flow it's getting. Horizontals have very weak flow compared to verticals. Try adding iron.