Diatoms

#1
My 29 gallon has been up and running for almost 3 months. Recently, I have seen the signs of brown algae. I've included photos hoping someone will help me identify. Is this what they call diatoms?

I do weekly water changes and clean gravel every time. My test readings are as follows:
Ammonia 0 Nitrite 0 Nitrate color falls between 5-10

Reading previous posts state that it is harmless and will disappear with time. I am very careful not to over feed. I also keep the lighting on a timer as suggested by the forum.

Is this an issue I just have to wait out?
 

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