Diatoms?

[Angel keeper]

So I have just noticed today when I did a gravel Vac that theres this brown and sort of powdered stuff in the substrate of my 5 gallon tank. I am thinking that it maybe diatoms, however this tank has be up and running for at least 3 years so im a bit confused about it being diatoms since they appear in newly set up tanks right?

Anyway previously I had bleeding heart tetras in the tank and I did not do a water change for at least a month which resulted in loads of algae building up, green and brown ones. This was mainly due to the UV light which I had and is replaced by a T8 bulb now. Could this algae be left over from the massive water changes I have done and gotten stuck in the gravel?

Will frequent gravel vacs fix this? I know if its Diatoms it will go away eventually so I would mind leaving it in there.

[Cliff]

Any way you could post a pic ?

[andreahp]

From what I've read about algae and the different kinds, I'm unfamiliar with lack of water changes causing it to grow - just too much light (whether natural or artificial). Not changing your water will lead to poor water parameters but many water changes won't cause algae to grow (as far as I know - lol)

[Trillianne]

From what I've read;

Diatoms are caused primarily by silicates in new tanks this is from the silicone seals leeching them into te water, and as they run out of silicate they essentially starve off and die.

While it is possible to see diatoms later on in a cycle it tends to be pretty rare since most people have city water, and getting enough silica deposits in water to cause them to grow at a noticeable rate is rather rare.

BBA when it first starts to show up can also look like the brown dusting of diatoms until it grows out into the more bushy look. Since you mention having algae before, I'd say its probably more likely that you had some spores of it floating about and they've started to recolonize.

[Lady Hobbs]

In the gravel bed, the brown is debris from food and waste. Diatoms are above the substrate and easily seen on decorations and glass. Removes easily and gone in a few months.