Cyanobacteria In Flooded Dsm Aquarium

Ivan747

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Jan 23, 2019
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Dominican Republic
Hi guys,

A few months ago I planted a tank and covered it using the dry start method. Then abandoned it for like 6 months. After weeding out some emersed weeds, I flooded the tank.

The plants are hairgrass, covering about 40% of the substrate currently and several stems of what I think is some type of rotala.

The hairgrass is very dense in some areas and very scarce in others.


I’m on week 2 and I have patches of Cyanobacteria growing in the substrate, this Cyanobacteria was introduced when I used tap water (my tap water has it apparently). I have since switched to filtered drinking water that I buy in 5 gallon returnable bottles, and the algae was receding but now it’s staying. There’s some diatoms as well but I find they always disappear on their own.

I’ve heard I should either reduce phosphates or increase nitrates... problem is my ferts are combined NPK, I can’t choose how much of each one I dose. Should I just dose more NPK and hope for the best?

Here are some measurements and specs of the tank:

Substrate: fluval plant and shrimp stratum
Aquarium: Mr. Aqua 12 gallon long (36”x9”x8”) it’s not the real deal, I had one made to the same measurements cause I can’t import the real deal
Filter: Aquaclear 20 on the right corner and Hagen Elite Mini filter on the left corner, acting as a nano powerhead. I have active carbon on the aquaclear because it was a new tank. I don’t know how much it affects the chelated minerals in the micros.
Fish: 6 newly introduced cardinal tetras (2 days in tank)
Light: Finnex 24/7 Planded Plus SE
CO2: pressurized tank, with diffuser


Nutrients:
Light: hard to define the photoperiod because the light fades in and out, but I will say 7-8 hours of effective photoperiod, and 3 hours of ambient light (the lights are at minimum brightness during these 3 hours)
CO2: 30ppm.
Other carbon: 1ml to 1.5ml of flourish excel daily. Helped eradicate some string algae.
Macros: a friend gave me a mix of what I think is GLA macros for EI method. It’s NPK mixed together. I dissolved this into a bottle with drinking water.
Micros: GLA CSM+. I dissolved these into a bottle with drinking water.
Dosing regime: EI method. Monday macros, Tuesday micros, Wednesday macros and so on. 50% change on Sunday.


Water parameters:
Before introducing the fish last Monday, I measured my water parameters. It was 24hrs after a water change and I dosed macros that day. This is measured with API liquid test kits.

pH: 6.0
Ammonia: <0.25ppm
Nitrites: 0ppm
Nitrates: <5ppm, I estimate 2.5ppm
KH: 2dKH
GH: 1dKH

As you can see, it’s very soft water, but it’s not RO/DI. I am a bit worried about the fact the ammonia was not 0ppm and that the nitrates were so low for a planted tank. Any comments?

Let me know what improvements I could make to try to get rid of this nasty bacteria. Hopefully it won’t come back.
 

Tim Harrison

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Jul 7, 2017
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Reduce your photoperiod to 6hrs and maintain good house keeping, clean filters, tank and larger water changes weekly etc. Also think about your light intensity, could that be reduced too?
I'd try to physically remove or syphon out as much of the Cyanobacteria as possible and add more KNO3. Failing all that, a 3 day black out; and no peaking...
 
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Ivan747

New Member
Jan 23, 2019
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Okay, first thing I'm gonna do is remove the last 3 hours of ambient light.
I have a window nearby with a shade and a curtain. I have noticed that from 8AM to 11AM some sunlight gets through. I used to keep the shade down but now I'm using the curtain (so 0 light from that window) and it has made a difference as well.

I'll try to find KNO3 on a gardening store. Any recommendations on how to calculate the dosing of it? I saw on the internet that is often sold as a pure salt.
 

Ivan747

New Member
Jan 23, 2019
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Dominican Republic
It was receding but it's back again. I must continue to remove it by hand :(

I did remove the last 3 hours of light at night, I don't know if it had to do with this.


Edit:

Thinking about the changes I have done since last week, I found the following things:
* I have started to feed the fish more since they have acclimated and are feeding more aggressively. I'll reduce the feeding once again, as long as they don't lose weight.
* I have stopped using the air conditioner at night so the temperature is a bit warmer (the aquarium is unheated because I'm in the tropics anyway). The lack of AC might have accelerated the cyanobacteria reproduction.
* I have noticed a find of foam or scum on the surface of the water, which might be affecting the oxygen levels. I have tried to remove this but it's not easy to get rid off without a skimmer. I'll try to remove it more aggressively.

I also increased the flow on the powerhead.


Edit 2:

Just found out that my sister fed the fish quite a lot earlier in the day, that must have been the problem that triggered the algae. I did a 15% water change siphoning out all the excess food and some algae. I wanted to change more water but that's all the water I have prepared and ready to go.

Hopefully I'll get back on track by next week.
 
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HHLaursen

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Jul 11, 2017
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Aalborg, Denmark
I have used the following method a couple of times with great success on different aquariums.


Remove the Cyano. Turn off the aquarium light and cover your aquarium completely, so that NO light enters, for four days and ad 10ml of hydrogenperoxid (3%) pr 100L pr day.
Uncover the aquarium and give your plants one day of normal light.
If any signs of Cyano, do a 50% water change and repeat step one.

I do not recommend doing step one more than twice, without giving the plants a month or so to recover.

In the this period you should not ad any food, fertilisers or co2.

Your plants would not look healthy, but they should survive.

You will never get rid of cyano as it is everywhere and airborne. But you can visibly remove it.

If your water is under 300 tds you should decrease the amount of hydrogenperoxide.
Let's say your water is 150tds then you should cut the amount in half.

Ex.
>300tds = no worries
300tds = 10ml pr 100 L pr day.
150tds = 5ml pr 100L pr day.

-do not use this method in a shrimp tank with pure RO water!

Sendt fra min ONEPLUS A6003 med Tapatalk
 

Ivan747

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Jan 23, 2019
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Dominican Republic
Thanks HHLaursen! I shall try it as my last resort, because the plants are doing so well I don’t want to hurt them. However, I think I could cut back on food for a few days, given that my sister naively added lots of food today. It’s okay though.

I also like the idea of hydrogen peroxide, more than the blackout to be honest.
 
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HHLaursen

New Member
Jul 11, 2017
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Aalborg, Denmark
You will have to do the four day blackout combined with the hydrogen peroxide.

The only thing cyano needs to survive is light and carbon...

If your fish is well fed, they will do fine without food for at least a month

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