Problem With Green Algae

[zephi]

I have a brackish tank with one puffer (toadfish), 3 gobies, 2 southern gurnard perch, shrimps, 4xcommon grazer(snail), one nerite.
Parameters:
nitrites <0.5
nitrates 20
pH 7.4
SG approx 1.012
I have no lighting, except for some sunlight (not direct).
It's quite well planted with seagrass and another type of plant which I'm not sure of, (looks like kelp). All is thriving.
Tank has been running for well over 5 months, but in the last 1.5months I've run in to major algae outbreaks

My little gurnard

As you can see in the photo, a lot of hair algae is growing on rocks, plants and on the driftwood. I don't mind this, because it suits a brackish environment i think.
My biggest problem is the green slimy algae which builds up on the glass every single day.(shown on the 3rd image) Also the water has a slight tinge of green(very visible during daytime. Some days I can't even see the other side of the tank. BUT at night its a little clearer, which is why these photos were taken at night.

During the day, when I look closely I can see the algae sinking slowly down to the bottom of the tank along the edge of the glass (could be spores, or it's splitting).
I've been manually removing each day, and it always returns the following day.

I'm currently performing a blackout for my tank. The regrowth rate has slowed down, but it still returns each day... My water color has become a light yellow tinge now. Currently its winter, I allowed the temperature in the tank to drop a bit, so the fish aren't as active. So over-feeding is not the factor.
Can anyone help me with this problem? I would like to be able to look at my tank during the day without the blur of the algae.

 

[Colin_T]

I would do some big water changes to dilute any nutrients in the water. Also increase the water movement & surface turbulence in the tank.
You can try adding some fine filter floss to the filter out the algae

 

[jtipton]

Add a batch of malaysian trumpet snails. Most pet storess give these away.

 

[zephi]

Add a batch of malaysian trumpet snails. Most pet storess give these away.

wont they get eaten by the puffer anyway? since they're not that big in size. I don't they think can fix the problem with the yellow tinged water.

 

[zephi]

I would do some big water changes to dilute any nutrients in the water. Also increase the water movement & surface turbulence in the tank.
You can try adding some fine filter floss to the filter out the algae

I'm afraid of doing big water changes, I wouldn't want another mini cycle to occur. Would doing 10% a day be okay? it will take a bit longer though.

Another question, is it recommend that I buy a heater for my tank? since it will be winter soon. But the thing is, these fish were collected at a local river which of course is affected by the winter temperatures.
Also could the colder weather cause algae bloom?

 

[Colin_T]

if the fish are from local waterways then they should be fine in an unheated tank over winter.

cooler condtions don't encourage algal blooms but they are often associated with it. This is because the fish don't eat as much when the water cools down but the hobbiest continues feeding them the same amount as usual. This leaves uneaten food to rot and feed the algae.

10% water changes don't dilute the tank very much. You are better off doing a 20-25% or more. If you make up the water a few days before using it, and get the PH, temp & salinity the same as the tank, there should be no reason for the filters to have a problem and do a mini cycle.
Mini cycles are usually caused by washing out the filter media in water that is different to where the filter has been living. ie: under tap water.

 

[zephi]

okay thanks for the tips.
last time the mini cycle was caused probably because of the SG and temperature difference, and also because I did a 40% water change.

I've had quite a few different algae growing in my tank before.
When the water became greenish, A lot of the green spot algae also disappeared off the glass, small patches of BGA disappeared as well.
Strangely enough, red & brown hair algae remains along with the greenish water and algae on the surface of the glass.


It's already been 4 days since I blacked out the tank. So far I noticed that the water has become a yellowish tinge (colour looks like tannins leaking out of driftwood), everything else remains the same. If I don't see green water, does that mean the green water algae is dying?

 

[Colin_T]

the yellowish colour, tannins, could be coming from driftwood or the plants dieing off.

if the water clears up and is no longer green then it is probable the algae has died. But algae often leave behind spores that can grow when the conditions are good. A couple fo water changes should dilute the yellow colour and if you can gravel clean the tank you should be able to remove the dead/dieing algae and its spores.

 

[zephi]

Could the tannins really be still leaking out? That was a driftwood I picked up a long time ago from the beach, and I've used it in my tanks for nearly 2 years. Could the algae growing over it decompose the wood and leak tannins out?

 

[ac106]

I would do some big water changes to dilute any nutrients in the water. Also increase the water movement & surface turbulence in the tank.
You can try adding some fine filter floss to the filter out the algae

I'm afraid of doing big water changes, I wouldn't want another mini cycle to occur. Would doing 10% a day be okay? it will take a bit longer though.

Another question, is it recommend that I buy a heater for my tank? since it will be winter soon. But the thing is, these fish were collected at a local river which of course is affected by the winter temperatures.
Also could the colder weather cause algae bloom?

Don't be afraid of water changes. You wont have a "mini-cycle" because of them. I have done 90% water changes trying to get nitrates down without a problem. Very little bacteria is in the water, It is mostly in the sand, rocks, wood and filter.

Carbon will clear up the water color but that is only dealing with the sympton and not the cause.

 

[zephi]

Don't be afraid of water changes. You wont have a "mini-cycle" because of them. I have done 90% water changes trying to get nitrates down without a problem. Very little bacteria is in the water, It is mostly in the sand, rocks, wood and filter.

Carbon will clear up the water color but that is only dealing with the sympton and not the cause.

Thanks for the advice. Just to be on the safe side I won't change TOO much water too quickly. Probably do a 20% water change tomorrow. Since its only algae there's no real rush, it's not life threatening to the fish as opposed to having high nitrates etc.

 

[Colin_T]

Could the tannins really be still leaking out? That was a driftwood I picked up a long time ago from the beach, and I've used it in my tanks for nearly 2 years. Could the algae growing over it decompose the wood and leak tannins out?

dead plants release tannins as well as wood. The wood might not be leaching them but the dead plant and algae might be.

 

[Fella]

I've gotta say while you might not like the algae on the front glass (it is a bit annoying...) otherwise your tank looks great and I'm quite envious of your selection of fish!

 

[nmonks]

Zephi, water changes DO NOT harm the filter bacteria. Provided the filter stays wet, you can change all the water at once if you want. There are essentially no filter bacteria in the water. All the filtration happens in the biological media, usually the filter in most aquaria.

I wouldn't worry about the algae. Manually remove what you want (e.g., from the glass) but otherwise leave the tank to settle down. Algae problems often settle down by themselves. Algae is a normal part of the aquatic environment, and it is much easier to accept it and use it as a decorative material than to fight the constant battle.

Cheers, Neale

Thanks for the advice. Just to be on the safe side I won't change TOO much water too quickly. Probably do a 20% water change tomorrow.

 

[dilbert]

I am not sure as with puffers but Malaysian Trumpet Snails are one the least snails that get eaten by anything due to their form of the shell.

But I doubt that they will fix the growth of algae.

When I tried out another phosphate test kit from API, I found it quite unsuitable for marine tanks and tried it on our brackish tank. That has a phosphate concentration of stunning 5 ppm!


Phosphates come mainly from rotting plant leaves (lots in there), fish food (flakes and frozen), and tap water. 20% water changes about every two weeks lower the concentration only to 4 ppm and this goes up then again during the following weeks.

The tank has the usual ammonia, nitrite, and nitrate all zero - at least with those not that sensible API tests (but sufficiently accurate for a brackish tank). The high phosphates is been said are not dangerous to any critters in the tank but algae grow well on phosphates.

As it would take extreme measures to get rid of all phosphates (or down to 0.03 ppm as in seawater), I would try those phosphate remover pads for filters or simply anywhere in the tank.

Taking out the algae manually - if possible - has the advantage that the phosphates are removed together with the algae whereas algae eating snails leave the phosphates in the tank (with their poo).