Cyano or Dino?

Aquarius74

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Trying to figure out what this is growing in my tank. Based on what I have read, Cyanobacteria or dinoflagellates seem most likely. Have been battling it for a few weeks now. 100 g reef rank established 8 months ago. Nitrates are low, at about 1ppm; phosphates are 0.16ppm. I am aware that very low levels of both would likely some sort of dino. Not sure how to interpret nitrates being low, but phosphates being fairly high. Any thoughts would be appreciated. Thanks!
20251122_183714_585B2967-4690-4EE5-BA39-4D74FA3DD24D.png

20251122_183714_EE9D837C-8A98-4484-96CC-5959D0A96C02.png

20251122_183714_93C8DE14-D38C-407F-93B1-73F0173CEA46.png
 

Subsea

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More details would help. However, low nitrate in a marine system is never good.
 
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Aquarius74

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These photos might be a little better. As for other details:

Salinity 1.026
Temp 77.5 F
pH 8.39
Nitrates undetectable
Phosphate .016

Tank is 100g and currently has low stock of fish. Currently have 2 clowns, a sailfin tang, an algae blenny, and cleaner shrimp. Also have a few small beginner corals and an anemone. Have been very slowly adding fish following a previous disease outbreak when tank was very new (now quarantining all new fish separately; more fish will be added in a couple of weeks).

Any thoughts on what this is are appreciated.

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20251123_132106_BE660F28-321B-4300-B22B-119D523ADA37.png
 

EnterName

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It's really hard to tell from the pictures because there is no real coloration to this bubble trapping stuff. Diatoms & Dinos tend to be brown, while cyanos are dark red or green. This apparently translucent stuff could be something completely different.

I feel like a microscope might be the easiest way to find out what it is. Maybe you know someone who has a microscope or you invest a few bucks in a used one. Even very cheap ones will suffice in most cases.
 
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Aquarius74

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It's really hard to tell from the pictures because there is no real coloration to this bubble trapping stuff. Diatoms & Dinos tend to be brown, while cyanos are dark red or green. This apparently translucent stuff could be something completely different.

I feel like a microscope might be the easiest way to find out what it is. Maybe you know someone who has a microscope or you invest a few bucks in a used one. Even very cheap ones will suffice in most cases.
Ok, thank you!
 

AB's reef

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The top photo looks like diatoms to me, 2nd photo I'm not sure, the green tinge makes me lean towards dinos.
 

Paullawr

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Trying to figure out what this is growing in my tank. Based on what I have read, Cyanobacteria or dinoflagellates seem most likely. Have been battling it for a few weeks now. 100 g reef rank established 8 months ago. Nitrates are low, at about 1ppm; phosphates are 0.16ppm. I am aware that very low levels of both would likely some sort of dino. Not sure how to interpret nitrates being low, but phosphates being fairly high. Any thoughts would be appreciated. Thanks!
20251122_183714_585B2967-4690-4EE5-BA39-4D74FA3DD24D.png

20251122_183714_EE9D837C-8A98-4484-96CC-5959D0A96C02.png

20251122_183714_93C8DE14-D38C-407F-93B1-73F0173CEA46.png
Difficult to ID in this light. I do not believe it to be dinos but is likely (very likely) a bacterial slime which thrive in low nutrient environments. It will be whiteish in colour, produce bubbles. Can be seen with hair like protrusions.

What ever additive / bacterial solution your adding, stop. If you're running a skimmer, I'd switch it off / take it out for a month. Be less aggressive with changing filter socks/filter material for that month also. See how you get on.
 

EnterName

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Was able to get a microscope and captured these images and video at 2000x. Any thoughts on what this is are appreciated.
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View attachment 20251125_132646_792F4970-93EB-4A58-B3E8-424F5B5D8515.mov
Did you mean 200x? Light microscopes don't really go beyond 1000x without getting useless. Visible light isn't capable of resolving enough detail.

It's neither diatoms nor the typical dinoflagellates. It might be bacterial growth, that's why you only see floating bits but nothing else. Most bacteria are really small and you need a good microscope to see them (and even then they will only be tiny).

1b47a76b-2a9b-4541-afc5-0bfe4fc670e5.jpg

The video isn't too clear, but do you see things like shown in the attached photo move? These guys can appear when overdosing carbon or in coral mucus. I try to attach a video but sometimes videos don't load.
 

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