ID please

[ReefTankAllTheWay]

Hello everyone. Happy holidays and coming New year.
My tank used to have green algae and able to support some snails and copepods. But over time, the green algae gradually disappeared and now covered with brown films. Snails died off and pods disappeared. I believe they were starved to death.
You can see the brown film is on my hand and covers the cheato. It is sticky and flows on water and stick to sand too. Please ID this and suggest a solution.

Ammonia, Nitrite = 0
Nitrate = 5ppm
Phosphate = 2ppm
Salinity = 1.025
Alk = 8.9dKh
Calcium = 497

Thank you

 

[kharmaguru]

Hello everyone. Happy holidays and coming New year.
My tank used to have green algae and able to support some snails and copepods. But over time, the green algae gradually disappeared and now covered with brown films. Snails died off and pods disappeared. I believe they were starved to death.
You can see the brown film is on my hand and covers the cheato. It is sticky and flows on water and stick to sand too. Please ID this and suggest a solution.

Ammonia, Nitrite = 0
Nitrate = 5ppm
Phosphate = 2ppm
Salinity = 1.025
Alk = 8.9dKh
Calcium = 497

Thank you
View attachment 32394443

Without a microscope any type of brown film growth is a guess. It's possible it's a toxic type of dinoflagellate which could be poisoning your grazers but again you would need a scope. You have very high phosphate relative to your nitrate and that is likely a factor as to what is preferentially growing. Aside from chaeto, how else are you managing nutrients?

 

[ReefTankAllTheWay]

I have a fleece filter roller and protein skimmer

 

[griss]

Have you run any GFO? That would help bring the PO4 down and, like Sean said, that might help resolve the issue.

 

[Sugar Magnolia]

I'm no expert but it could be dissolved organic compounds collecting on your cheato.