sounds like cyano or diatoms. maroonish color is usually cyano and rusty brown is usually diatoms. you may check the water you are using for top off and water changes. if you are using treated tap water, it is probably cyano because of the phosphates you are getting in your tap water.

if the tank is still cycling, unfortunately, this is something you will probably deal with for a while. just keep doing your water changes and try to use RO/DI water or DI water from the store (in the gallon jugs).