What has caused this

[PeterEde]

This tank is now 2 years old. Ive struggled with nitrate for ages but never had algae like this.
My nitrates have been as high as 60ppm but for 6 months plus have managed to get it to around 20ppm
Phosphate is at .04.
I am dosing 16ml of ethanol daily.
I feed once a day.
Tank does get afternoon sun.
Fish are all healthy
Notice gsp has been pretty closed up for sometime

 

[Saltyreef]

I had persistant algae like that. Dosing pods and phyto really helped along with manual removal during water changes.

 

[Baldyreef]

I had persistant algae like that. Dosing pods and phyto really helped along with manual removal during water changes.

Same here I had a really bad hair algae outbreak that would keep coming back and only got rid of it until I added pods and did a ton of manual removal

 

[Mr. Mojo Rising]

With that much algae, IMO the nitrates are higher than what the test shows. One thing we can't test for is dissolved organics, if the nitrates up to 60 it gives me an impression that dissolved organics level is likely very high as well, feeding the algae. I would perform water changes and remove manually and keep going until its gone.

 

[PeterEde]

Thanks for replies