Corals turning brown

[MrBubble47]

Hello everybody!

I've got a 20 gallon reef started in march 2020 with many different types of corals.
I've been away for 3 weeks and when I came back I've seen some corals that have turned brown and others not doing too good.
In this period of type I dind't dose any trace elements, could this be the reason why this happened?
I've got osmotic water coming out at 10tds, could this also be the reason?

Thanks to everyone that answers

 

[Randy Holmes-Farley]

Trace element issues are unlikely.

Maybe overfeeding boosted nutrients that boosted zoox levels (causing the browning).

 

[MrBubble47]

Trace element issues are unlikely.

Maybe overfeeding boosted nutrients that boosted zoox levels (causing the browning).

I see, actually my Bubble Magus skimmer has had some problems that i could't fix before my departure so it has been off for 3 weeks. That could be the reason then... Thank you very much Randy!

 

[Stuartmercer]

What is your lighting? I lack in lighting creates a response in the corals to create more zooxanthellae (The part that gives them nutrients). zooxanthellae are usually brown and so a large amount of them in the corals tissue can create that brown look.

 

[MrBubble47]

What is your lighting? I lack in lighting creates a response in the corals to create more zooxanthellae (The part that gives them nutrients). zooxanthellae are usually brown and so a large amount of them in the corals tissue can create that brown look.

Hello Stuart! My lights are pretty terrible, I must say. I have got Nemo Light II 96w. After just 8 months the UV leds are burning the lenses. Anyhow the Acropora and the Seriatopora caliendrum are glued in the top part of the rockscape, near the LEDs, so they should recieve plenty of light.
Before my departure I've added carbon and zeolite (Sicce Akuacler) and many algae that covered the rocks disappeared but at the same time I switched off the skimmer so I don't know if it's a nutrient excess... Do you think it is a lighting issue?

I'll post more pictures so you can see better.

 

[Stuartmercer]

Hello Stuart! My lights are pretty terrible, I must say. I have got Nemo Light II 96w. After just 8 months the UV leds are burning the lenses. Anyhow the Acropora and the Seriatopora caliendrum are glued in the top part of the rockscape, near the LEDs, so they should recieve plenty of light.
Before my departure I've added carbon and zeolite (Sicce Akuacler) and many algae that covered the rocks disappeared but at the same time I switched off the skimmer so I don't know if it's a nutrient excess... Do you think it is a lighting issue?

I'll post more pictures so you can see better.

I do see alot algea, could you please post the nutrient levels? And based on the algea I see and the fact you say your lighting isnt great, I am guessing it could be mix of the two. Also is your tank old and stable enough for acropora? how old is your tank?

 

[MrBubble47]

I do see alot algea, could you please post the nutrient levels? And based on the algea I see and the fact you say your lighting isnt great, I am guessing it could be mix of the two. Also is your tank old and stable enough for acropora? how old is your tank?

O course! My tank is 10 months old. I tested the water yesterday and I've then corrected the KH wich had gone down quite a bit. All tests are Salifert, here are the results:
pH: 8,2
KH: 7,7
Ca: 390
Mg: 1320
No3: 0
Po4: 0
Si: 0

In another Forum some people told me that the algae compromises the tests and that it makes it look like it does not have any nitrate or phospate... is it possible?

 

[Stuartmercer]

O course! My tank is 10 months old. I tested the water yesterday and I've then corrected the KH wich had gone down quite a bit. All tests are Salifert, here are the results:
pH: 8,2
KH: 7,7
Ca: 390
Mg: 1320
No3: 0
Po4: 0
Si: 0

In another Forum some people told me that the algae compromises the tests and that it makes it look like it does not have any nitrate or phospate... is it possible?

Yes the amount of algae I see could easily compromise the results shown by the test kit.

Based on this, I do think that it is a nutrient and possibly a lighting issue. There is not much that you can do other than keep the algae under control. I suggest going in every couple days to manually remove as much algae as you can, and do small water changes maybe 1 or 2 times a week.

 

[MrBubble47]

Yes the amount of algae I see could easily compromise the results shown by the test kit.

Based on this, I do think that it is a nutrient and possibly a lighting issue. There is not much that you can do other than keep the algae under control. I suggest going in every couple days to manually remove as much algae as you can, and do small water changes maybe 1 or 2 times a week.

I see, okay I'll definately do many water changes to try to take away that stuff that makes those algae grow like that.
Here's one last pic that better shows the type of algae growing in my tank. Do you know what's their name?

 

[Stuartmercer]

I see, okay I'll definately do many water changes to try to take away that stuff that makes those algae grow like that.
Here's one last pic that better shows the type of algae growing in my tank. Do you know what's their name?

I see alot of bubble algea - a good emerald crab will take care of that
And there is some hair algea I think.

 

[MrBubble47]

I see alot of bubble algea - a good emerald crab will take care of that
And there is some hair algea I think.

I've searched for their names on the browser it looks like the one on the top left corner is a Caulerpa racemosa. The other little one growing everywhere looks like an Acetabularia calyculus.
The idea of introducing the green emerald crab sounds great! Do you think it'll feed on these algaes too?

 

[Stuartmercer]

I've searched for their names on the browser it looks like the one on the top left corner is a Caulerpa racemosa. The other little one growing everywhere looks like an Acetabularia calyculus.
The idea of introducing the green emerald crab sounds great! Do you think it'll feed on these algaes too?

I only know of them eating bubble algea. They might though.

 

[MrBubble47]

I only know of them eating bubble algea. They might though.

Thank you very much!
I'll ask the friends at the Macroalgae topic to see what they think about it

 

[Bepis]

Thank you very much!
I'll ask the friends at the Macroalgae topic to see what they think about it

Make sure to get a female. Males eat corals!

 

[MrBubble47]

Make sure to get a female. Males eat corals!

Hi Bepis! I just got it today plus a pink urchin. The crab immediatly started to eat the algae. Let's hope that it'll do its job.