I have taken over a tank which has an infestation of brown hair algae and diatoms, which is rampant. It grows incredibly fast and looks like large brown dust or tumbleweed. I use a turkey baster to blow it off of plants and substrate and then vacuum it out of the tank. I'm doing water changes and lowering the lighting but it's a very persistent algae.
Do you know if the tank is near a window, or possibly, if you are possibly ovefeeding or someone else is? I’ve found for those three algae types, you must have somewhere that extra nutrients are coming into it your tank (that lets the algae grow), especially when it comes with brown algae since it’s primarily fed on tanks that have an imbalance of nutrients and excessive lighting conditions.
The tumbleweed affect may be hair algae that isn’t getting fed well enough and turning brown (dying off) but leaving a mess as it does this, which than is letting the other algae grow on it since it’s in prime locations for growth.
Firstly, the brown algae has to be removed physically from the tank. Proper lighting has to be provided from about 6-8 hours. RO water that is free from nitrates and silicates will not allow the growth of brown algae in tanks. Any sign of brown algae has to be tackled in the initial stages itself otherwise it will grow into a terrible menace for the whole fish tank.