# Brown Diatoms, dosing and lights?



## Aquaticz (Dec 26, 2009)

I have had this myself. Typically is newer tank. I would do two things, maybe 3
1. keep filter clean
2. Tank may be going through mini cycles, how much of a WC are u doing.
3. If light drives CO2 and together they promote growth...try cutting back on the light for a few days and see if that has an effect


Last but not least, it seems to me that the more plants the better. Ido not know exactly why, but to me it seems to be able to tolerate more when packed.


Hope this helps u
Lexus know your results


Sent from my iPad using Tapatalk HD


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## Seattle_Aquarist (Jun 15, 2008)

Hi Golightly,

Or, the easiest method to control diatoms is to add an Otocinclus or two. Otos eat diatoms like I eat ice cream; typically I have at least one Oto per 10 gallons of aquarium volume.


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## AlyeskaGirl (Oct 6, 2011)

How old are your light tubes?


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## DarkCobra (Jun 22, 2004)

At 35par, this is a low light tank. With so little light to start with, you can't afford to lose much before plants start to struggle.

In my low light tanks, any time I see this algae in this growth pattern, I know that's what has happened. Typically I find the splash guards are obviously quite dirty, and a good cleaning solves the problem; though it may take a week or two to see the result, as all changes occur slowly in low light. If I find the guards need cleaning more frequently than in the past and when only a little dirty, and I know the bulbs are years old, then it's time for new bulbs.

And finally, if the guards have to be kept meticulously clean to avoid this even with known good bulbs, I know I'm making things harder on myself than necessary by providing an insufficient light margin; and look into increasing the light slightly.

There are other possibilities, of course. Your parameters, if correct, eliminate many of them. I assume you're also providing enough potassium, iron and other micros, and not overfeeding.


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## Golightly (Jan 14, 2011)

AlyeskaGirl said:


> How old are your light tubes?





DarkCobra said:


> At 35par, this is a low light tank. With so little light to start with, you can't afford to lose much before plants start to struggle.
> 
> In my low light tanks, any time I see this algae in this growth pattern, I know that's what has happened. Typically I find the splash guards are obviously quite dirty, and a good cleaning solves the problem; though it may take a week or two to see the result, as all changes occur slowly in low light. If I find the guards need cleaning more frequently than in the past and when only a little dirty, and I know the bulbs are years old, then it's time for new bulbs.
> 
> ...


I have 3 LED light units set to 40% power, I can easily raise that but I'm trying to avoid problems with algae by using lower light levels. (The lights are in pristine condition and very high quality.)

Do you think it's because of low light levels? In my experience the higher light the more diatoms I get.




Seattle_Aquarist said:


> Hi Golightly,
> 
> Or, the easiest method to control diatoms is to add an Otocinclus or two. Otos eat diatoms like I eat ice cream; typically I have at least one Oto per 10 gallons of aquarium volume.


I already have 5 Oto's and 20 or so Shrimps.




Aquaticz said:


> I have had this myself. Typically is newer tank. I would do two things, maybe 3
> 1. keep filter clean
> 2. Tank may be going through mini cycles, how much of a WC are u doing.
> 3. If light drives CO2 and together they promote growth...try cutting back on the light for a few days and see if that has an effect


My filter is spotless, I clean it every week and use filterwool to trap any particles. The water is crystal clean.

I do 30% weekly water changes with 2/3 RO and 1/3 Tap water.


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## DarkCobra (Jun 22, 2004)

Golightly said:


> I have 3 LED light units set to 40% power, I can easily raise that but I'm trying to avoid problems with algae by using lower light levels. (The lights are in pristine condition and very high quality.)
> 
> Do you think it's because of low light levels? In my experience the higher light the more diatoms I get.


Hmm.

After increasing light, the algae may briefly increase, as it responds faster than the plants. Takes about two weeks for a new balance to visibly establish. If you've run at higher lighting for at least that long with no benefit, I'd say insufficient lighting is not the problem; or perhaps the overall plant mass and growth is insufficient reach the tipping point for a new balance even at the higher light.

There is always the possibility that your sand and/or rocks are releasing a massive amount of silicates. But changing that is a last resort.

So that this point, there are no easy answers. If it were my tank, I'd get a bit experimental, changing multiple parameters at once:

1) Increase surface agitation if there's even the slightest chance O2 levels are insufficient. You may lose some CO2, but that's ok because...

2) Over a week, gradually cut CO2 levels in half. 30+ ppm isn't an absolute requirement at both low light and high flow. Reducing acidity will slow the rate at which silicates dissolve, if this is indeed an issue.

3) Simultaneously and gradually increase phosphate levels until doubled. The presence of that small bit of GSA can be an indicator of low phosphate. Higher nitrate levels also require higher phosphate levels in my experience, even if the phosphate level is generally considered sufficient for plant growth. Though there isn't a ratio that must be exactly followed, 40:1.8 is a bit extreme.

And then of course wait to see what develops. If there's an improvement, remove the changes one at a time to isolate which was responsible.


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## Seattle_Aquarist (Jun 15, 2008)

Golightly said:


> I'm having persistent problem with brown diatoms in a mature planted tank (1+ year). I'm trying to figure out what I'm doing wrong, if it's a in-balance with fertilizers, NO3, PO4 or too much light?
> 
> Majority of the diatoms are on the sand and rocks (which i don't mind too much) but it's also on the lower leaves of the stem plants making them look dirty. There isn't much on the glass, but at the glass at the back of the tank were I left some diatoms it's producing some green spot algae now (taking over from diatoms?)
> 
> Can anyone advice what it might be?


Hi Golightly,

In doing so research I found an interesting article that diatoms are not typically found in polluted bodies of water but only cleaner water sources. Maybe our tanks are too clean??


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## BruceF (Aug 5, 2011)

Are you dosing anything?


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## Golightly (Jan 14, 2011)

BruceF said:


> Are you dosing anything?


Yes, I dose a complete fertilizer daily (Tropica).



DarkCobra said:


> Hmm.
> 
> After increasing light, the algae may briefly increase, as it responds faster than the plants. Takes about two weeks for a new balance to visibly establish. If you've run at higher lighting for at least that long with no benefit, I'd say insufficient lighting is not the problem; or perhaps the overall plant mass and growth is insufficient reach the tipping point for a new balance even at the higher light.
> 
> ...


Thanks for all the advice and ideas. Definitely a lot to try out there. I'm first going to increase the light slightly but also try and aim for a 10:1 ratio of NO3 vs PO4. I might not actually need to dose Macro's in this tank so will see how it goes with the ratio if I only do Micro's.


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## herns (May 6, 2008)

A friend of mine has this problem solved last week in his tank by reducing photo period and light intensity.


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## Golightly (Jan 14, 2011)

Update. Still Diatom problems, but it's changing in places.

All low growing plants and the bottom parts of the bigger plants are all covered in diatoms, all the leaf edges are brown. The rocks are absolutely covered in diatoms, but dying out in patches.. seems to be replaced by green algae of some kind. Sand is probably the worst really brown in some places.

Changed nutrients and lights:

NO3: *10ppm*
PO4:* 0.9ppm*
CO2: drop checker light green
Light: *40-50par* (increase it from 30par)
Water: 2/3 RO and 1/3 tap water

I only use Micro fertilizers as without me adding any macro's it stays around a constant NO3 of 10-11ppm. But plants are not growing very fast, it all seems very slow.

The lace plant is heavily covered in diatoms, where it should be green it's gone brown and probably wont survive.

Desperately need some help!

What am I doing wrong?


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