Brackish Planted Aquarium

[zephi]

My brackish tank has been flourishing as soon during summer here in Australia. Now it's autumn...
Anyway, in my tank these plants started popping out of nowhere, can anyone identify them?

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With all these plants growing, I've also got some hairy filamentous algae growing, patches of blue-green algae, and other small plants growing attached to the rocks. The algae is kept to a minimum, but does anyone know a good way of totally eliminating the blue-green algae? It's growing on top of the sand, rock, as well as on the hairy algae.
I've tried removing them by hand, and some break off and grow elsewhere... Will they eventually die as nutrients are taken up by the plants? Any methods without damaging my plants or organisms living inside the tank?

 

[nmonks]

The sheet-like algae is Ulva, so something similar. It's harmless, and actually good to eat. The salinity must be fairly high if Ulva are growing since they're mostly marine algae. Your tank looks lovely, from what I can see in the photos, so I'm not really sure why you're bothered by the algae. I'd just crop back by hand what you don't want, and feed it to scats, tangs, or any other algae-eating fish you happen to have.

Cheers, Neale

 

[zephi]

The sheet-like algae is Ulva, so something similar. It's harmless, and actually good to eat. The salinity must be fairly high if Ulva are growing since they're mostly marine algae. Your tank looks lovely, from what I can see in the photos, so I'm not really sure why you're bothered by the algae. I'd just crop back by hand what you don't want, and feed it to scats, tangs, or any other algae-eating fish you happen to have.

Cheers, Neale

Thanks Neale for your quick reply. I love the ulva, its so beautiful in the tank. Only thing I'm concerned about is when they start to die off as winter hits, BGA might take over the tank, since it's already coating a lot of the other plants and algae growing on the rocks and sand.

 

[nmonks]

The Ulva (a green alga) and blue-green algae (cyanobacteria) are favoured by different things, so provided you optimise for the one and work against the other, you shouldn't have any major problems. In any case, algae contains little protein, so even if it dies, it shouldn't add much by way of nitrates to the water compared to the livestock.

Cyanobacteria are favoured by three things: direct sunlight, slow water movement, and abundant nutrients (esp. nitrate and phosphate). I find that cyanobacteria appear first where the water flow is weakest, e.g., around the roots of floating plants or on the substrate. Adjusting/increasing water flow can be a big help.

Cheers, Neale

 

[zephi]

The Ulva (a green alga) and blue-green algae (cyanobacteria) are favoured by different things, so provided you optimise for the one and work against the other, you shouldn't have any major problems. In any case, algae contains little protein, so even if it dies, it shouldn't add much by way of nitrates to the water compared to the livestock.

Cyanobacteria are favoured by three things: direct sunlight, slow water movement, and abundant nutrients (esp. nitrate and phosphate). I find that cyanobacteria appear first where the water flow is weakest, e.g., around the roots of floating plants or on the substrate. Adjusting/increasing water flow can be a big help.

Cheers, Neale

Yes they are flourishing around where there is very little water flow. I've already set the filter output to the max hoping to get rid of them. Is there a way to kill them off like... For the ones growing on the sand surface, can you simply bury them under the sand to kill them off?
As for the livestock, the biggest culprit I think are the "mullet", the fish seem quite messy, constantly pooing everywhere... They eat a lot of detritus and poo a lot at the same time... But in turn the plants flourished after I introduced them in the tank.

 

[nmonks]

No. Besides physically removing them or poisoning them with erythromycin, which is a temporary fix at best, the only solution is to correct whatever problems in the tank are encouraging their growth. If you simply siphon them out or poison them, they will be back in weeks if conditions suit.

Cheers, Neale

Is there a way to kill them off like...

 

[zephi]

thanks for you replies, I've cropped some of the ulva out which was blocking some of the water flow on the sand. Hopefully the BGA will clear out soon. If that doesn't help I'm going to change the direction of the water currents.
Would plants and the ulva take up nutrients much faster than BGA? I'm thinking of getting some other small plants in the tank.

 

[nmonks]

The addition of plants or other types of algae won't make any difference if the other issues such as water flow aren't fixed first. If anything, pockets of still water around plants can act as focal points for new blue-green outbreaks.

As I've said before, blue-green algae is promoted by a set of environmental issues that need to be solved as a group. Focus on these. In tanks with lots of water flow, no direct sunlight, and plenty of fast-growing plants, blue-green algae as good as never happens.

Cheers, Neale