What bacteria is this?

edbl · Oct 22, 2025

Hey guys! About 2 and a half weeks in my first saltwater tank (nothing but macroalgae) and over the last couple days ive been noticing a growth in some brownish green algae. Theres some little bubbles on some spots too. Not too educated on diatoms dinos and cyanos but im convinced its at least one of them. Can anyone help id it and maybe give some suggestions on how to get rid of it? Thank you!

Nitrates are looking at around 5 ppm but no clue about the other nutrients. I also use rodi water. (Planning on getting testers soon)

Tinnerito · Oct 23, 2025

edbl said:
Hey guys! About 2 and a half weeks in my first saltwater tank (nothing but macroalgae) and over the last couple days ive been noticing a growth in some brownish green algae. Theres some little bubbles on some spots too. Not too educated on diatoms dinos and cyanos but im convinced its at least one of them. Can anyone help id it and maybe give some suggestions on how to get rid of it? Thank you!

Nitrates are looking at around 5 ppm but no clue about the other nutrients. I also use rodi water. (Planning on getting testers soon)

Can I see a photo under white light?

EnterName · Oct 23, 2025

2.5 Week old tank sounds like Diatoms. A picture with neutral (white) light would help though.

Just know that it doesn't matter if it's dinoflagellates or diatoms. Your tank is still developing and you don't need to take action. In fact disturbing what is currently happening might prolong the inevitable.

After the diatoms are gone, green hair algae will take over the tank. This is also normal. A quick web search on "the ugly phase" should answer most of your questions.