# Brown diatoms in mature tank (ARGH!)



## Alplily (Jan 1, 2012)

Brown diatoms all over my 36g tank, mosses, plants. Looks terrible!

Tank is mature. I feed fish (there are 12 small mixed fish in there and one pearl gourami) only a tiny bit each day, and nothing over the weekend. I have not rescaped. There have been no disruptions or changes.

I added four ottos... they seem to be eating anything and everything else but the diatoms. The ottos are not touching anything on the mosses. They focus on keeping one plant clean.

I also have a few ramshorn snails and CRS in there, but nothing I can't sacrifice if absolutely necessary. I breed CRS in a different tank, and can repopulate if needed. For example, would removing the fish and overdosing with Flourish Excel possibly work?

This tank looked sparkling clean for months before the diatoms took over.

What to do??? If the tank were not so big, I would have thrown it out my second story office window by now.


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## DennisSingh (Nov 8, 2004)

Bump, no ones got a good answer for diatoms?


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## BruceF (Aug 5, 2011)

My take these days is clean, clean, clean. Especially the filters. I added some kno3 and phosphate two weeks ago and the next day the plant leaves were coated in brown slime. No fish. No co2. I don't know how you are running your tank so perhaps you have some other problem. For me keeping things clean, not adding too much n,p,k and a decent amount of flow works pretty well.


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## Alplily (Jan 1, 2012)

Thanks... I dose with Flourish Excel 3x/week. No other nutrients except root tabs.

Tank levels are balanced. HOB filter for a 50g runnning in the 36 g, so flow is good.

I will try doing a major clean with 50% water change?


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## zzrguy (Jul 11, 2012)

My tank is just cycled and the brown tide is rolling in. Im trying to cut the light and dose with CO2 bosster to see if it will stop it. I have no algae eating fish in yet. 

I had a outbrake in my 5gal and it was running for 9 months. I dosed it with co2 booster and it died off in a week of dosing every day.


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## cradleoffilthfan (Jan 19, 2009)

When was the last time you put in the root tabs, they only last 3 to 6 months. Didn't know if you had replaced them at all. Also, when the bulbs in light fixtures go bad sometimes you will get a little diatom bloom. Test phosphates and nitrates and make sure they are within a good range.


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## RainSong (Jun 30, 2011)

I feel your pain ... I have been going through the same thing. My 90 gallon is over a year old and I have diatoms galore. I have posted questions about it here with no satisfactory answer. I will follow this thread with interest ... good luck!


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## tetra73 (Aug 2, 2011)

Diatom is caused by the presence of silica in the water, substrate, and sand. Since the tank is matured (not sure how long you have the tank), the silica has to be be introduced from the tap water, water change. You can get Phoslock to remove both phosphate and silica before doing your WC.


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## DogFish (Jul 16, 2011)

Alplily said:


> ....I will try doing a major clean with 50% water change?


Use RO or distilled water and see what happens. You might need to do two large water changes in one month to really flush out the tank.


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## RainSong (Jun 30, 2011)

tetra73 said:


> Diatom is caused by the presence of silica in the water, substrate, and sand. Since the tank is matured (not sure how long you have the tank), the silica has to be be introduced from the tap water, water change. You can get Phoslock to remove both phosphate and silica before doing your WC.


Not sure if I agree ... I have 2 tanks. The one with the Eco-Complete substrate is covered in diatoms. The one with the sand substrate has no diatoms. WC for both tanks comes from the same source (tap).


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## Alplily (Jan 1, 2012)

Hi all, I have been swamped by life since I posted this. I will try some of your suggestions. Thank you for the responses.

Other clues based on the above:
I do have Eco-Complete in there.
Root tabs are replaced sporadically at best.
I use half tap water and half RO when I can.
I use the same substrate and water in a 10 gallon, and no trouble with diatoms there.
The lamps have been on the fixture for about a year now. May need replacing.


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## flc (Sep 10, 2012)

RainSong said:


> Not sure if I agree ... I have 2 tanks. The one with the Eco-Complete substrate is covered in diatoms. The one with the sand substrate has no diatoms. WC for both tanks comes from the same source (tap).


Judging from your locale, your tap water is very high in silica. Any water source filtering through the cascades, columbia basin, or palouse is going though rock that used to be ocean floor before it came up as magma, ash, tephra, or lava.

Freshwater diatoms are always present in tap water. They're enriched for by conditions that include, but are not limited to, low light, pH 6.8, low kH, low Ca, low Mg, high silica, and high concentrations of normally environmentally limiting nutrients found in high concentrations in fish foods, such as phosphate and iron in an organically available form.

Clearly, one of your tanks has those conditions and the other doesn't.


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## concepts88 (Oct 4, 2012)

See my thread here. Not sure if it is the same but..

http://www.plantedtank.net/forums/showthread.php?t=193000

and it made my tank CRYSTAL CLEAR


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