Mystery algae?

Mandarin the first · Mar 24, 2024

Can anyone help identify what is taking over my tank? I don’t have access to a microscope to check it accurately.
Parameters:
Salinity 1.026
Temp 78f
Po4 0 (Hanna ulr)
No3 0.25ppm (red sea pro)
Alk 8.7
Cal 440
Mag 1340

I cannot get detectable nutrients (apart from some nitrates when I feed really heavy) due to whatever this is sucking po4 and no3 up. Most of it can be blown off with a turkey baster easily and turns into almost a dust. However by the next day or two it grows back to how it was. Doesn’t seem to disappear at night from what I can tell. Am ready to start dosing nutrients to detectable levels depending on what this is.

Dan_P · Mar 25, 2024

Mandarin the first said:
Can anyone help identify what is taking over my tank? I don’t have access to a microscope to check it accurately.
Parameters:
Salinity 1.026
Temp 78f
Po4 0 (Hanna ulr)
No3 0.25ppm (red sea pro)
Alk 8.7
Cal 440
Mag 1340

I cannot get detectable nutrients (apart from some nitrates when I feed really heavy) due to whatever this is sucking po4 and no3 up. Most of it can be blown off with a turkey baster easily and turns into almost a dust. However by the next day or two it grows back to how it was. Doesn’t seem to disappear at night from what I can tell. Am ready to start dosing nutrients to detectable levels depending on what this is.

I don’t see how this much biomass can be removed by blowing it off the rock and then it grows back in a day.

The organism looks like filamentous algae and it looks infested with a brown slime, maybe dinoflagellates. It might also be harboring cyanobacteria. When algae is stressed from low nutrients and high light intensity, it turns ugly like this. It also seems to be unappetizing to snails.