FW-Brown algae issue

I'm seeking advice for a friend of mine. He's had his planted tank set up for at least a month now. Prior to that, it housed turtles. It's a 30 gallon tank with a 2-bulb, T-5 HO, 6500 K bulb lighting fixture. The lighting cycle runs 12 hours a day. He doses carbon excel and has a DIY carbon diffuser made using yeast in a milk jug.

He is having a brown algae issue that he just can't seem to shake. It's covering his gravel, rock and plant leaves and it seems to be getting worse.

Any input?

Thanks you.

 

What's in there now for fish? A Pleco may take care of the alge, but I'm not sure if they will eat the plants too.

 

Look for 2n10 as he is quite versed in freshwater planted tanks.

He taught me that if the nitratehosphate ratio is out of balance and you have higher light and are only dosing carbon you will get algae.

Is your friend using fertilizers? They are needed with carbon dosing and higher light.

 

2x angel fish and 2x gourami.

 

I've told him that he needs to fertilize, but he doesn't (yet). If it's a balance issue, then it's an easy fix.