Brown Algae on subsrate and rocks

I have the same problem. And my tank has been running for 2 years now. Until recently, I moved to a new place, so I didnt do water change for a month - so this algae bloomed.
I did water change 50%, but as you said, it comes back almost the next day.

Phosphate and nitrate are negligible in my tank and I am using Tap water. So now, I am doing a blackout of the tank (covered with garbage bag) for 2-3 days.
Then I figured that my lights might be the cause since i've never changed them for 2 years. So I ordered new lighting as well. I'll see if that helps.

P.S. Tank = JBJ nano 12 Deluxe

 

Yes the bulbs might be another reason for us. Also just to let everyone know having this issue and following this thread, I was reading last night and I didn't put as much importance to the power-head as needed. I am running a 425 Koralia from my old 30g and a 500 Gph on the other side which the propellers are worn from hitting snails. I read that having the right amount of circulation prevents algae along with benefiting a lot of other things such as coral. So check out if your running the right GPH in circulation. Hope this helps.

 

Diatom on subrate and rocks

I think I have found soucre of problem,when i purchased brine shrimp from LFS, I was putting the shrimp along with the water they came in into my tank without knowing the source of the water from the LFS.After a few water changes and putting the shrimp and not the water I am starting to notice less of the diatoms.I will to continue the water changes and hopefully that was the source of the problem.

 

I have also been battling this same problem since I set my tank up (about 6 months). I've pretty much concluded that it is because I do not use RO/DI water, it's the next item I will buy for my tank when I get the money. For the time being however I have found that a sand-sifting type goby, (mine is a Twin-Spot) and some blue and red legged hermit crabs do a nice job on the sand bed, and Turbo Snails do an excellent job on the rocks, not so good on the glass tho so I still have to use a magnet scraper to clean it up. Just my 2 cents.