Can anyone ID this algae please

Joffunswife

Community Member
View Badges
Joined
Jul 26, 2025
Messages
45
Reaction score
13
Rating - 0%
0   0   0
Hi all. I have this algae in my nano tank and I’m not sure if it’s just part of the good old ugly phase or something else.

Under blues it looks a lot more brown.

There are some stringy bits at the front that are easily 6inches long.

Thank you!




 

Freenow54

5000 Club Member
View Badges
Joined
Mar 5, 2021
Messages
6,561
Reaction score
5,092
Location
Ontario Canada
Rating - 0%
0   0   0
Can you supply a picture under white light? Sounds like Hair Algae. If so and if you can assuming its on your rocks remove rocks and scrub clean. It will take a while as it comes back but will suddenly disappear. Your info is very sketchy sorry with a picture send to #reefsquad
 
OP
OP
Joffunswife

Joffunswife

Community Member
View Badges
Joined
Jul 26, 2025
Messages
45
Reaction score
13
Rating - 0%
0   0   0
Apologies, I did add two photos but they seem to have vanished.

I will add them again here

This is as white as my Maxspect lights go.

#reefsquad

WhatsApp Image 2025-09-23 at 22.00.31_893b4d88.jpg

WhatsApp Image 2025-09-23 at 22.00.31_737623ca.jpg
 
Last edited:

Troylee

all about the diy!!!!!
View Badges
Joined
Jan 15, 2010
Messages
22,204
Reaction score
23,360
Location
Vegas baby!!!!
Rating - 0%
0   0   0
It could possibly be a start of Dino’s but hard to tell really… if you stir the top of the sand right there do they come back after a couple hours? Is it gone in the morning and gets worse as the day goes on?
 

Freenow54

5000 Club Member
View Badges
Joined
Mar 5, 2021
Messages
6,561
Reaction score
5,092
Location
Ontario Canada
Rating - 0%
0   0   0
To me I am no expert that is normal . You cannot stop Algae growth without chemicals Which I hate and this forum is full of people who have killed fish ect with them I use snails. There are lots of natural ways. Also a UV light if you want I am looking into them and apparently don't cause any harm and work but not the cheap all in one types. It takes some research to understand them as well flow ie exposure time to the light is key
 
OP
OP
Joffunswife

Joffunswife

Community Member
View Badges
Joined
Jul 26, 2025
Messages
45
Reaction score
13
Rating - 0%
0   0   0
It could possibly be a start of Dino’s but hard to tell really… if you stir the top of the sand right there do they come back after a couple hours? Is it gone in the morning and gets worse as the day goes on?
I don't know if it comes back after stirring the sand but I will find out in the morning. It's not gone in the morning and doesn't seem to get worse as the day goes on as far as I can tell. I will double check on this though
 

Freenow54

5000 Club Member
View Badges
Joined
Mar 5, 2021
Messages
6,561
Reaction score
5,092
Location
Ontario Canada
Rating - 0%
0   0   0
It could possibly be a start of Dino’s but hard to tell really… if you stir the top of the sand right there do they come back after a couple hours? Is it gone in the morning and gets worse as the day goes on?
I am replying to you Troylee I did not notice the sand. Do you think #ds ultraviolet light works? Or Uv Lights to Sterilize them Works?
 

EnterName

Well-Known Member
View Badges
Joined
Sep 21, 2025
Messages
808
Reaction score
1,931
Location
Germany
Rating - 0%
0   0   0
First of all: If you are expecting the ugly phase to begin then you don't need to worry about it. In 99% of all cases problems will disappear on their own once the microbiology has developed a little bit.

The two options Dinoflagellates and Diatoms were already mentioned but it's usually a good Idea to give some context:

1. Diatoms are the first type of algae that visibly takes over a tank during the ugly phase. There aren't many competitors in the first few weeks/months for them and new dry sand can release quite a lot of silicate into the water which diatoms use to create their outer "shell". To prevent further silicate from entering the system you only need to make sure the RO/DI water you use is properly deionized. If you have your own RO/DI system you will need a measuring device for that, otherwise it depends on your water source/seller what you can do.

2. Dinoflagellates are feared by many when appearing in established tanks, but they are usually harmless during the ugly phase. They are associated with very low nutrient levels which are common in new tanks (whether they are the cause or symptom of low nutrient levels doesn't matter too much right now). Either way, they are capable of photosynthesis and some are known to eat diatoms. This means even in young tanks with very limited nutrients they can thrive but most likely vanish once the diatoms are gone. If they don't disappear within the first months we can talk about how to get rid of them. I wouldn't really recommend a UV sterilizer, or even chemicals right now as your tank is still developing.

You don't need to do anything for now besides ensuring the RO/DI water is properly deionized and maybe adding some copepods. This way you already have some little beneficial helpers that actually eat diatoms and dinoflagellates and will provide a great food source for your fish in the future. Turn off the water flow when adding them so they don't end up in the skimmer immediately. If you already have fish in your tank you can add them at night when the light is off so they don't get eaten right away.
 

Freenow54

5000 Club Member
View Badges
Joined
Mar 5, 2021
Messages
6,561
Reaction score
5,092
Location
Ontario Canada
Rating - 0%
0   0   0
First of all: If you are expecting the ugly phase to begin then you don't need to worry about it. In 99% of all cases problems will disappear on their own once the microbiology has developed a little bit.

The two options Dinoflagellates and Diatoms were already mentioned but it's usually a good Idea to give some context:

1. Diatoms are the first type of algae that visibly takes over a tank during the ugly phase. There aren't many competitors in the first few weeks/months for them and new dry sand can release quite a lot of silicate into the water which diatoms use to create their outer "shell". To prevent further silicate from entering the system you only need to make sure the RO/DI water you use is properly deionized. If you have your own RO/DI system you will need a measuring device for that, otherwise it depends on your water source/seller what you can do.

2. Dinoflagellates are feared by many when appearing in established tanks, but they are usually harmless during the ugly phase. They are associated with very low nutrient levels which are common in new tanks (whether they are the cause or symptom of low nutrient levels doesn't matter too much right now). Either way, they are capable of photosynthesis and some are known to eat diatoms. This means even in young tanks with very limited nutrients they can thrive but most likely vanish once the diatoms are gone. If they don't disappear within the first months we can talk about how to get rid of them. I wouldn't really recommend a UV sterilizer, or even chemicals right now as your tank is still developing.

You don't need to do anything for now besides ensuring the RO/DI water is properly deionized and maybe adding some copepods. This way you already have some little beneficial helpers that actually eat diatoms and dinoflagellates and will provide a great food source for your fish in the future. Turn off the water flow when adding them so they don't end up in the skimmer immediately. If you already have fish in your tank you can add them at night when the light is off so they don't get eaten right away.
Interesting Stuff. It all rang true for me on my own build. The only thing I hope you are wrong about is that the sand you buy has Silicate in it. I just added sand to my new tank today and the bag stated clearly that it was silicate free.
 

Troylee

all about the diy!!!!!
View Badges
Joined
Jan 15, 2010
Messages
22,204
Reaction score
23,360
Location
Vegas baby!!!!
Rating - 0%
0   0   0
I am replying to you Troylee I did not notice the sand. Do you think #ds ultraviolet light works? Or Uv Lights to Sterilize them Works?
Uv sterilizers work great for most Dino’s.. some are stubborn and don’t leave the water column so you gotta work at it by stirring them up and getting them Into the light..
 
OP
OP
Joffunswife

Joffunswife

Community Member
View Badges
Joined
Jul 26, 2025
Messages
45
Reaction score
13
Rating - 0%
0   0   0
First of all: If you are expecting the ugly phase to begin then you don't need to worry about it. In 99% of all cases problems will disappear on their own once the microbiology has developed a little bit.

The two options Dinoflagellates and Diatoms were already mentioned but it's usually a good Idea to give some context:

1. Diatoms are the first type of algae that visibly takes over a tank during the ugly phase. There aren't many competitors in the first few weeks/months for them and new dry sand can release quite a lot of silicate into the water which diatoms use to create their outer "shell". To prevent further silicate from entering the system you only need to make sure the RO/DI water you use is properly deionized. If you have your own RO/DI system you will need a measuring device for that, otherwise it depends on your water source/seller what you can do.

2. Dinoflagellates are feared by many when appearing in established tanks, but they are usually harmless during the ugly phase. They are associated with very low nutrient levels which are common in new tanks (whether they are the cause or symptom of low nutrient levels doesn't matter too much right now). Either way, they are capable of photosynthesis and some are known to eat diatoms. This means even in young tanks with very limited nutrients they can thrive but most likely vanish once the diatoms are gone. If they don't disappear within the first months we can talk about how to get rid of them. I wouldn't really recommend a UV sterilizer, or even chemicals right now as your tank is still developing.

You don't need to do anything for now besides ensuring the RO/DI water is properly deionized and maybe adding some copepods. This way you already have some little beneficial helpers that actually eat diatoms and dinoflagellates and will provide a great food source for your fish in the future. Turn off the water flow when adding them so they don't end up in the skimmer immediately. If you already have fish in your tank you can add them at night when the light is off so they don't get eaten right away.
Thank you.
We make our own RODI water and it tests at 0 tds. We also already have a lot of Copepods as well. They are also topped up bi weekly. We have already been through one ugly stage but I have been told that it is a repeated process sometimes. The tank was only started mid June so I’m not expecting it to be anywhere near pretty yet.
 

Freenow54

5000 Club Member
View Badges
Joined
Mar 5, 2021
Messages
6,561
Reaction score
5,092
Location
Ontario Canada
Rating - 0%
0   0   0
Uv sterilizers work great for most Dino’s.. some are stubborn and don’t leave the water column so you gotta work at it by stirring them up and getting them Into the light..
Sorry my post was not clear. I have a dedicated hand held UV light made my a member he goes by 3 not # so 3D. Don't have the problem so have not used it. there are always questions by others if it works, Thought you might know
 

EnterName

Well-Known Member
View Badges
Joined
Sep 21, 2025
Messages
808
Reaction score
1,931
Location
Germany
Rating - 0%
0   0   0
First of all: If you are expecting the ugly phase to begin then you don't need to worry about it. In 99% of all cases problems will disappear on their own once the microbiology has developed a little bit.

The two options Dinoflagellates and Diatoms were already mentioned but it's usually a good Idea to give some context:

1. Diatoms are the first type of algae that visibly takes over a tank during the ugly phase. There aren't many competitors in the first few weeks/months for them and new dry sand can release quite a lot of silicate into the water which diatoms use to create their outer "shell". To prevent further silicate from entering the system you only need to make sure the RO/DI water you use is properly deionized. If you have your own RO/DI system you will need a measuring device for that, otherwise it depends on your water source/seller what you can do.

2. Dinoflagellates are feared by many when appearing in established tanks, but they are usually harmless during the ugly phase. They are associated with very low nutrient levels which are common in new tanks (whether they are the cause or symptom of low nutrient levels doesn't matter too much right now). Either way, they are capable of photosynthesis and some are known to eat diatoms. This means even in young tanks with very limited nutrients they can thrive but most likely vanish once the diatoms are gone. If they don't disappear within the first months we can talk about how to get rid of them. I wouldn't really recommend a UV sterilizer, or even chemicals right now as your tank is still developing.

You don't need to do anything for now besides ensuring the RO/DI water is properly deionized and maybe adding some copepods. This way you already have some little beneficial helpers that actually eat diatoms and dinoflagellates and will provide a great food source for your fish in the future. Turn off the water flow when adding them so they don't end up in the skimmer immediately. If you already have fish in your tank you can add them at night when the light is off so they don't get eaten right away.
Interesting Stuff. It all rang true for me on my own build. The only thing I hope you are wrong about is that the sand you buy has Silicate in it. I just added sand to my new tank today and the bag stated clearly that it was silicate free.
I notice brown stains (diatoms verified through microscope) every time I add some new sand to the tank without rinsing and letting it soak in RO/DI for a few days. It's dry "AquaMedic Coral Sand" which naturally contains some silicate and even though there might be better products available I never had a serious issue with it.

It never gets beyond some brown discoloration so it's not a big deal, but in new tanks even slightly elevated silicate levels seem to cause a lot more diatom growth so I tend to warn people about it.

As I'm currently in the process of changing tanks I will look into other substrate options, maybe I will find some nice aragonite substrate that doesn't have this issue and looks good.
 

Troylee

all about the diy!!!!!
View Badges
Joined
Jan 15, 2010
Messages
22,204
Reaction score
23,360
Location
Vegas baby!!!!
Rating - 0%
0   0   0
Sorry my post was not clear. I have a dedicated hand held UV light made my a member he goes by 3 not # so 3D. Don't have the problem so have not used it. there are always questions by others if it works, Thought you might know
Are you referring to a uv sweeper? If so yes they work but again you gotta put in the work to get them into the light.. a friend of mine made one and it worked very well he said.
 

OrionN

Anemones
View Badges
Joined
Jul 28, 2013
Messages
11,302
Reaction score
22,511
Location
Corpus Christi, TX
Rating - 0%
0   0   0
Hi all. I have this algae in my nano tank and I’m not sure if it’s just part of the good old ugly phase or something else.

Under blues it looks a lot more brown.

There are some stringy bits at the front that are easily 6inches long.

Thank you!
A picture worth a thousand words
 
OP
OP
Joffunswife

Joffunswife

Community Member
View Badges
Joined
Jul 26, 2025
Messages
45
Reaction score
13
Rating - 0%
0   0   0
Hi all. I have this algae in my nano tank and I’m not sure if it’s just part of the good old ugly phase or something else.

Under blues it looks a lot more brown.

There are some stringy bits at the front that are easily 6inches long.

Thank you!
A picture worth a thousand words
There are pictures above
 

OrionN

Anemones
View Badges
Joined
Jul 28, 2013
Messages
11,302
Reaction score
22,511
Location
Corpus Christi, TX
Rating - 0%
0   0   0
I did not see any picture yesterday. Must be the server on the blink.
I agree with many advices above. Just leave them be. Stir the sand a bit if you wish. Normal progression of the fauna of the tank.
 

TOP 10 Trending Threads

WHAT AMOUNT OF LIVE ROCK AND SAND SHOULD BE PRIORITIZED FOR OPTIMAL BIODIVERSITY/FILTRATION?

  • 100% live rock + bagged sand

    Votes: 34 28.1%
  • 100% dry rock + 100% live sand

    Votes: 41 33.9%
  • 50/50 live/dry rock, 50/50 live/bagged sand

    Votes: 27 22.3%
  • 75% live rock, 25% live sand

    Votes: 11 9.1%
  • 25% live rock, 75% live sand

    Votes: 8 6.6%
Back
Top