Brown Algae

Kirkland

I have some brown algae growing. I understand it supposed to be part of the cycle. I find different theories about having the light on or not. Should I keep the light to a minimum or not? Thanks

1077

If there are live plant's in the tank I would start with eight hours of light.
If what you are seing (brown algae) is diatoms, then it should clear from the tank after a few weeks.
You can take a clean paper towel folded into fourths,and wipe down the glass but i would refrain from disturbing the decor,substrate,or filter if the tank is cycling.

Kirkland

Thanks for the help. There's no live plants in the tank. Does that mean I should use less light?

Byron

The answer to your question depends upon what you want, as I'll explain.

Fish do not need light, they would be quite happy with only daylight coming in to the room; most are forest fish that occur in very dimly-lit waters shaded by overhanging plants and the forest canopy. With plants, light is obviously essential for photosynthesis, and the plants in balance will normally keep algae minimal. Without plants, the light is only needed for your viewing, to better see the fish.

Algae is a plant, and thus needs light and nutrients. In a tank without the higher plants, there will be plenty of nutrients from the fish waste, food, respiration, etc., so algae will appear in proportion to the light. Algae is not a bad thing, it fact it is quite good. Without higher plants, the algae will help control the organics and maintain somewhat better water conditions, much as the higher plants do only much more in their case. And some algae is quite decorative; after all, those so-called moss balls are actually just a type of algae. It is up to you how much algae you want, and the light is the best way to control it.

We are speaking here of various types of green or red (black) algae. The brown is likely diatoms, and that occurs usually in new tanks and then no more. However, it can appear later in low light, or with silicates (a type of mineral) if these are in the tap water.

Byron.

Kirkland

Thanks, that's a really good explanation. I appreciate your insight

mermaidqueen

I never had any algae while my tank was cycling. And after it had cycled, I went for many months without any algae. The only live plants in it are floating plants and mossballs on the substrate. All the other plants are artificial.

Recently, back in March, I did two things different that have caused diatoms to appear on the glass for the first time: I put one of those vacation feeding blocks into the tank before leaving on a ten-day vacation, and I had trimmed back some of my floating Hornwort.

Obviously, the first one added more nutrients to the tank, and the second let in more light. I have never had really bright light in my tank, which is a 20-gallon-high, Aqueon. I just have the single fluorescent bulb that came with it, and have always used that. It give off low to medium light, only.

I don't have a lot of diatoms -- just a few small patches on the rear and side glass panel. And a very small patch in the lower right-hand corner of the front pane. None at all on the opposite end pane. The places where they are showing up are places where the canopy of floating plants doesn't cover, and more light comes through.

I have read contradictory information regarding light and diatoms. Some have said they develop in low light and that brightening the light would get rid of them. Other sources have said exactly the opposite. Which is true, I can't say, except to describe my own lighting situation and what I now have in the way of diatoms.

Diatoms are harmless. They can be easily removed with a gentle scrubber during water changes.

I have well water, and I use gravel for a substrate. No silicates that I know of. If I had these, the diatoms would have appeared from the beginning. As I've stated above, my tank has been set up for many months, and only since March have the diatoms appeared.

-- mermaidqueen

Kirkland

I turned off the light for the last 2 days and when I woke up this morning almost all of the algae(diatoms) had disappeared. Amazing how nature works

mermaidqueen

And that's exactly the opposite of what I've been told -- that they thrive in the lower light, and it takes a really bright light for them to disappear. Also, that diatoms aren't true algae. Sometimes it's hard to know what to believe.

-- mermaidqueen

kirkland14

I put an albino pleco in there and turned off the light. I'm pretty sure he didn't eat it all in two days. I'm going with the lights off theory IMO.
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Byron

A pleco could well handle all the diatoms very quickly. Diatoms (brown algae) and common green algae are very easy to keep in check as many fish will readily and eagerly devour them. I have had diatoms in a 90g tank be wiped out within a day by a trio of otos. Pleco, otos, Farlowella, etc. However, one must ensure the tank can handle extra fish before adding any, and of course one has to want the fish on its own merits. They add to the bioload which can cause other issues. Not saying this applies here, just general info for those reading.