Return of diatoms?

[swifty]

My tank had a diatom bloom (which I learned is common) a few weeks after I setup my tank in January. It lasted until about Feb-March. Since then my tank has been in a pretty good balance.

When I upgraded my tank and a week before the upgrade, I started noticing some brown algae on the leaves of my amazon swords. I reduced feeding thinking it was a overfeeding issue, but it still remained. Before the upgrade I did some re-scaping so I'm thinking I might have kicked up too much sand which threw some nutrients in the water. The upgrade may have done more as well, since I didn't rinse it completely in fear of losing some beneficial bacteria (I'm using black sand).

Is the only form of brown algae in diatoms, is there another cause? Not sure if I should just wait it out like my diatom bloom months ago, or do something.

I should mention it's just on the leaves of my swords, none on the rocks/glass/sand.

 

[Rivercats]

Some types of sand can release silicates. I don't do sand substrates but I do know that.

 

[aqua_chem]

First off, if you have any doubt as to what the algae is, you can post a picture of it just to be sure. Some forms of BBA and BGA can look similar to diatoms in some circumstances.

Second, what did "upgrading the tank" involve? New substrate? Rivercats is absolutely correct in that new substrates (sand especially but not exclusively) are often the causes of a diatom bloom.

 

[swifty]

Its on maybe 5 of the 20+ leaves I have in there.

When I upgraded from my 20g long to a 29g, all I did was transfer the old substrate from the 20g and placed it in the 29g.

 

[aqua_chem]

Does said algae rub off between your fingers fairly easily?

 

[swifty]

Yeah, I rubbed it off some of the leaves 2 weeks ago and it returned like that.