Stubborn Staghorn

[Florin Ilia]

Hi,

Warning, long post!

My tank was set up initially early this year and was reset in June. It is still my "lab" tank - an acrylic 12g that my son received for Christmas The light is around 60 mmol/s2 at the substrate, filtering is done with an Eheim 2078 turning around about 10x tank volume per hour. I am dosing (slight variations of):
1/8 tsp KNO3 3x a week
1/32 tsp KH2PO4 3x a week
1/32 tsp CSM+B 3x a week
All with a 50% weekly water change.
Lights are on 9-14, 17-22. I have pressurized CO2 which follows the light regime (but starts a bit early) and the concentration seems to vary a lot during the day.

Fauna is made of 5 corys, 6 otos and snails.

Here are some pics in chronological order, after the June reset. Please keep in mind, the goal of this tank is NOT good looks but just me being able to grow plants and critters safely:

June, right after planting:

A week later:

Another week later:



Staghorn begins - here, on a L repens leave: (at this point, I intentionally did not remove the algae to see how bad it gets)

It got bad: (following pictures are from late July)









The plants leaves are covered with "dirt" and show some signs of curling:



Then I went in a holiday and got back mid-August, after 2 weeks. Here's what I found:

After cleanup:

And about 10 days ago I switched to new plants:
- Some specimens from the previous generation (L. repens, R. rotundifolia, T. fluviatilis)
- Staurogyne repens
- Rotala macrandra
- Rotala sp. (?)
- Myriophyllum aquaticum
- Cyanotis sp. "Athraxon"
Right after planting:



And finally, pics from a few days ago. Closeup of R macrandra:



and general:



I am currently investigating whether my CO2 regime is too fluctuating and maybe that's what's causing the Staghorn but Scott reminded me that I hadn't posted any background to my questions - so here it is.

 

[scottward]

I'm seeing some brown 'freckles' on the leaves of a plant that looks like H.Polysperma.

I had these brown freckles also - the soon turned to holes - classic CO2 instability sign I think.

It is good that you aren't confusing low CO2 with unstable CO2. There are plenty of tanks with low CO2 that do ok. Tanks with unstable CO2 do much worse (like mine used to before Tom and the guru team helped me out).

Let's see what others think about the freckles and other indicators in the tank...

Scott.

 

[ShadowMac]

I'm in agreement that it is unstable CO2. I think the diffusion method could be to blame. Looks like you are using an airstone. I would suggest a ceramic disc diffuser or an atomizer so that the bubbles are very small and get moved around the tank by the current.

 

[Florin Ilia]

Thanks Scott and Mac for the replies!

a plant that looks like H.Polysperma

That's Ludwigia repens.

Tanks with unstable CO2 do much worse

Yeah that sounds like a good lead to follow.

I think the diffusion method could be to blame. Looks like you are using an airstone. I would suggest a ceramic disc diffuser or an atomizer so that the bubbles are very small and get moved around the tank by the current.

The airstone you see in the picture is for air. For CO2 I am using an inline diffuser like this one: http://rover.ebay.com/rover/1/711-5...0001&campid=5338187531&icep_item=280733572423 .

But that doesn't mean that my diffusion is on par. As others have pointed out in my CO2 thread, my tank seems to take too long gassing up and down - which confirms your suspicion.

 

[jerrybforl]

IME it comes from not having your lights, ferts, and CO2 balanced. How much light are you running? How many hours? How long does your CO2 run? These all play roles and are important to coming up with a solution to your problem. Let us know.

 

[scottward]

IME it comes from not having your lights, ferts, and CO2 balanced. How much light are you running? How many hours? How long does your CO2 run? These all play roles and are important to coming up with a solution to your problem. Let us know.

Very good details here: http://www.barrreport.com/showthread.php/9091-Stable-enough-CO2

 

[Florin Ilia]

For the benefit of people who will find this thread looking for Staghorn:
I am now completely Staghorn free. These are the changes I made to my tank, in the order that I feel (can't prove scientifically but I have a hunch) that were helpful:
Helpful:
- increased aeration via an airstone
- reduced fishload (from about 1cm fish/liter to about 0.6 cm fish/liter)
- aggressive physical removal of the algae
Maybe it mattered:
- increased CO2 after extensive experimentation
I don't believe it mattered:
- increased light from about 55 to about 75 µm/m2/s

Good luck!

 

[dutchy]

Staghorn is besides CO2 also related with having some NH4 in the tank. Mostly seen with tanks that have not cycled yet or when no water change has been done after moving/uprooting plants. Typically around one to two weeks later after the NH4 spike it will bloom.