Brown Algae

[N4T4SH45]

Hi

Can anyone please tell me what causes so much brown algae and how I can get rid of it?

Thanks

 

[@ombomb]

Brown Algae is very common and is generally caused by excess Nitrates in your water.

The best way to remove it is with a good algae scraper / gravel vac, perform regular water changes and keep your nitrates down.

 

[N4T4SH45]

Our Nitrate level is reading 0, as is our Ammonia and Nitrite levels

 

[@ombomb]

Hmmm... do you have any fish in the tank?

Is it heavily planted?

Unless the tank is completely uncylced, I doubt that Nitrates would be 0. What test kit are you using? Nitrate test kits don't last all that long, so the kit may be giving you an incorrect reading.

 

[N4T4SH45]

Yes we have fish

2 balloon mollies
3 male guppy
5 neon tetra
5 other neon, cant remember the name
2 silver tip neon

We only have plastic plants in the tank

The tank is completely cycled now. I cant remember the name of the test kit we are using buts in one which includes tests for Ammonia, PH, High PH, Nitrate and Nitrite (I will see if I can get the name of the kit when I pop in to the store at lunch time). It says it has a total of 700 water tests

 

[The-Wolf]

brown algae is actually diatoms.
Diatoms are caused by lack of light and can be eliminated by either adding more light sources or having the existing lights on for longer.

start at having the lights on for 10hrs then increase by half hour increments untill it is gone (max 14hrs)

diatoms are very common in new set ups, I'm guessing the tank is less than 8 weeks with fish in it.

Fish that eat diatoms are SAE (Siamese Algae Eater) L027 royal pleco and otocinclus (otos).
Otos are quite sensative and should only be added to a matured tank. L0027s can be quite expensive.

 

[@ombomb]

It sounds like the API Master Test Kit to me (good buy) but with that level of stock, you MUST be getting an incorrect reading. Are you remembering to give the bottles a good shake before doing the test? If you've had the kit for a while, I'd recommend replacing the Nitrate kit and testing again.

From www.thetropicaltank.co.uk:

"Brown algae" (diatoms)

This is often the first algae to appear in a newly set-up tank, where conditions have yet to stabilise. It will often appear around the 2-12 week period, and may disappear as quickly as it arrived when the conditions stabilise after a couple of months. It is essential to minimise nutrient levels to ensure the algae disappears - avoid overfeeding and carry out the appropriate water changes, gravel and filter cleaning, etc. Limiting the light will not deter this algae, as it can grow at low lighting levels and will normally out-compete green algae under these conditions.

If brown algae appears in an established tank, check nitrate and phosphate levels. Increased water changes or more thorough substrate cleaning may be necessary. Using a phosphate-adsorbing resin will also remove silicates, which are important to the growth of this algae. However, as noted above, it is essentially impossible to totally eliminate algae with this strategy alone. Due to its ability to grow at low light levels, this algae may also appear in dimly lit tanks, where old fluorescent bulbs have lost much of their output. If a problem does occur, otocinclus catfish are known to clear this algae quickly, although you may need several for larger tanks, and they can be difficult to acclimatise initially.

There are some very plausible theories as to why this algae often appears in newly set up tanks and then later disappears. If the silicate (Si) to phosphate (P) ratio is high, then diatoms are likely to have a growth advantage over true algae types and Cyanobacteria. Some of the silicate may come from the tapwater, but it will also be leached from the glass of new aquaria, and potentially from silica sand/gravel substrates to some extent. Later, when this leaching has slowed, and phosphate is accumulating in the maturing tank, the Si ratio will change in favour of phosphate, which is likely to favour the growth of green algae instead.