Algae Idenfication/destruction

[mangoed]

Hi,

Could anyone help to identify the predominant green algae type in the photos below and recommend any steps toward its eradication?

(It actually looks worse in digital photos than to the naked eye but, to either, it is rather unsightly.)

When I moved house, and aquarium, 10 weeks ago I decided to try sand instead of gravel in an unplanted setup (with rocks as decoration). My decision was primarily due to the year-long battle, ultimately lost, against other algae in a previous planted installation.

The substrate is approximately 5cm of Eco-Complete (I wanted to keep my options open regarding future planting) covered with CaribSea Super Natural Marine Sand (this is a tropical freshwater, not marine, aquarium but the sand is inert and should, apparently have no effect on pH or KH).

The algae appears to infest the sand itself and has proven extremely difficult to remove. It does spread to the rocks (as can be seen) and onto the glass sides of the tank but, since I can remove the former for scrubbing and simply wipe the latter, it isn’t so much of a problem in those locations.

The tank receives no direct sunlight and the water contains no measurable concentrations of either nitrates or phosphates. I have tried reducing the lighting period to 8 hours but this has no noticeable effect.

Any ideas?

 

[shelaghfishface]

cant help, but your not alone i get this in my biorbs,its a royal pain

 

[Colin_T]

It is blue green algae (Cyanobacter bacteria). You can suck it out and it re-grows in a few days. It spreads in sheets and covers everything rapidly and feels like snot. It smells musty when removed from the water.
It is commonly caused by excessive nutrients and low oxygen levels. Too much dry food and lack of water movement encourage it. Lights with a lot of red colour in them, and old globes can encourage it.
Cut back on feeding and remove any uneaten food.
Do daily gravel cleans and water changes and try to remove as much as possible.
Increase the water movement in the tank. Adding an airstone is a good idea.
Add some shrimp to clean up little bits of uneaten food.
Replace the globes if they are more than 12 months old. Use globes with a temperature or Kelvin (K) rating between 6,000K & 14,000K. Globes with a 10,000K are great if you can get them.
Some people have had success using antibacterial medications but care must be taken because many medications can wipe out the beneficial filter bacteria.
If the above fails and the problem is still occurring after a month you can try blacking out the tank for 3 days. Basically you turn the lights off and cover the tank so no light gets in. Leave if completely dark for 3 days and nights and that often kills it.

 

[Aphotic Phoenix]

Cyano-bacteria is nasty, and annoying stuff...tried doing blackouts and after those failed a round of anti-biotics took care of mine.

 

[shelaghfishface]

well thankyou from me xx

 

[mangoed]

Hi,

Thanks for your reply. I will examine for texture and scent tomorrow!

From your response, I can identify five issues:

1) Excessive nutrients
2) Low oxygen
3) Too much uneaten dry food
4) Lack of water movement
5) Colour/age/temperature of lighting tubes

It seems, perhaps, that (1) and (3) are linked (presuming that you are referring to the nutrients in the excess food)? Are (2) and (4) also linked (low oxygen caused by lack of water movement)?

Will adding an air-stone, as you suggest, increase water movement or just oxygen supply? Is it worth measuring the amount of dissolved oxygen or using a circulation pump (e.g. Hydor Koralia)?

The filter is a [Hagen] Fluval 205 and the capacity of the tank is 150L (probably reduced to around 120L by the gravel/sand) which is about 40 US Gallons. It should circulate about 420L (105 US Gallons) per hour.

The globes are Arcadia T5 Plant Pro (24W x 2) but I am having difficulty determining their temperature (it doesn’t appear on the packaging and I can’t find it on the Arcadia website). They are, however, about 14 months old.

I have recently reduced the amount of dry food being administered and will continue to ensure that an appropriate amount is delivered.

-dan

 

[Aphotic Phoenix]

Very curious where the low-oxygen hypothesis comes from?

My tank has quite a bit of gas-exchange and water flow, and had cyano-bacteria just as bad as my betta tank which has virtually no water movement. The commonality between the two was light: In the main tank-2 WPG with an inability to keep CO2 levels up (2x HoB filters isn't the best choice for planted tanks XD ), and the betta tank sitting in front of a window. Nitrate levels of both are kept about equal with the tap...20 ppm.


*Edit* Should note that after I made a huge fuss (and had to treat the tank), other people in the house stopped leaving the tank lights on so long. No re-occurance of the cyanobacteria in the main tank since then...the untreated betta tank still grows it where the sun hits most strongly.

 

[CKlown]

Very curious where the low-oxygen hypothesis comes from?

My tank has quite a bit of gas-exchange and water flow, and had cyano-bacteria just as bad as my betta tank which has virtually no water movement. The commonality between the two was light: In the main tank-2 WPG with an inability to keep CO2 levels up (2x HoB filters isn't the best choice for planted tanks XD ), and the betta tank sitting in front of a window. Nitrate levels of both are kept about equal with the tap...20 ppm.


*Edit* Should note that after I made a huge fuss (and had to treat the tank), other people in the house stopped leaving the tank lights on so long. No re-occurance of the cyanobacteria in the main tank since then...the untreated betta tank still grows it where the sun hits most strongly.

Out of curiosity (and being plain naive), why are 2x HoB filters a bad choice for planted tanks? Are you saying they somehow reduce CO2 levels or something?

 

[Colin_T]

Yep nutrients and uneaten food are the biggest cause. Dry foods will definitely encourage it.

Low oxygen and poor water movement are also linked. Poor water movement in particular but increasing the oxygen levels around the algae seems to help slow its growth. Adding an airstone will increase water movement and oxygen in the water. You can also use water pumps/ powerheads to provide more water movement but unless you increase the surface turbulence it won’t increase the oxygen level. Don’t bother about testing for oxygen, it’s not necessary and the kits cost heaps.

Fluoro globes usually have the temperature/Kelvin rating stamped on one end of the globe. Some globes don’t but most do. If the globes are about 14 months old I would look into replacing them with a couple of 10,000K globes.

 

[shelaghfishface]

im with whoever said not enough gas exchange causes this, as the biorb filter pump is rubbish, and the other tank (320) has no movement at all- due to the fact the filter isnt on at the moment, it will lift off in small sheets ( i had it when i had sand in a nother tank, and was a pain as it mixed easily into the sand when trying to lift it)
i would be tempted to try a blackout on the tank, what about that flourish excell( is that the name) stuff,would that work?


EDITED to spell properly-well nearly

 

[mangoed]

Hi,

Thanks again for all the replies - I will attempt as many of the suggestions as possible!

The only reason I’m reluctant to use an air-stone is that some posters suggest that the fish become accustomed to the higher levels of dissolved oxygen and therefore its possible future withdrawal would be detrimental to their health. The reason for such action would be that others assert that air-stones (especially running them during ‘daylight’ hours) are incompatible with a planted aquarium due to their tendency to drive CO2 from the water. The aquarium is not currently planted but I would like it to be in the future.

The filter creates a reasonable amount of surface turbulence – should this not be enough to oxygenate the water?

I meant to say in my last post that I did have some shrimp in the previous setup but they died (for reasons unknown) or, at least, there were none remaining when I moved the aquarium to my new house!

-dan

 

[oakes]

I have only had one outbreak of this stuff and your pics brought back some bad memories! The cause became apparent when i also noticed the appearance of some planaria. So i cut back on food and temporarily increased water change and gravel vac frequency.

In my case it also actually helped to increase the period of lighting. This encouraged the growth of normal algae at the expense of the nasty stuff which can grow under low light conditions since it is not actually an algae. Once i had plenty of healthy green algae i never saw the cyano again. This may be why some people advocate the use of flourish or other phosphate free fertilisers?

 

[Colin_T]

The airstone, extra oxygen and water movement, is only necessary to get rid of the stuff. Once it has gone you can remove the airstone and cut back on water movement and water changes.

Any surface turbulence will help remove carbon dioxide (CO2) and help encourage oxygen (O2). So regardless of having an airstone or just the outlet from the power filter near the surface, you will be driving out CO2 at the expense of the plants. However, there is plenty of CO2 in the air and plenty more being produced by the filter bacteria and the fish. So unless you are running a CO2 unit on a heavily planted tank, it won’t matter at this stage if you increase the oxygen levels in the tank. And again, once the Cyanobacter is gone you can reduce the surface turbulence and start adding CO2 for the plants if you want to.

Regarding fish becoming accustomed to the high O2 levels, most fish naturally occur in water bodies with high oxygen levels. The main place you will find a low O2 level is in a planted tank where people add supplemental CO2 for the plants. An excess of CO2 will cause more harm to the fish than low or high O2 levels. You can have low O2 and low CO2 levels in a tank and the fish will be fine. However, if you have low O2 and high CO2 levels the fish will die.
The other place you will find low O2 levels is in shallow pools out in the sun. As the water warms the O2 levels decrease and the fish create more CO2 that causes them to suffocate.

At this stage you should try to get rid of the blue green algae and then worry about setting up the planted tank.

 

[mangoed]

Thanks, I've ordered a whole bunch of stuff to address the issues you identified.

I've also read that Cyanobacteria are associated with extremely low nitrate levels. The NO3 in the aquarium tests as 0 (and the tap water as approximately 5ppm). The local Water Quality Report suggests that it should be about 43ppm so the discrepancy seems a bit strange. Presumably the 5ppm from the tap water and any additional nitrate being produced by the filter bacteria is being consumed by 'algae' (not necessarily the cyanobacteria).

I don't know enough to understand whether this is a causal relationship - i.e. whether raising the level of nitrates would help to erradicate the bacteria (or whether I'd just experience a proliferation of other algae instead of or in addition to).

-dan

 

[Colin_T]

In some tanks, primarily new marine tanks, there is often a type of Cyanobacter that develops. It is red in colour and is commonly called red algae. This stuff grows in tanks that haven't developed a natural balance and as such people say it grows because of low nitrates. It will also grow in tanks with high nitrates.

Some tap water has nitrates and other supplies don't. You are lucky and have only a bit of nitrate in your tap water. That is better for you and the fish.
In your situation you are better off cleaning up the tank conditions and changing the lights before you worry about adding things to try and get rid of it.