Cyno, Spirulina or something else?

[vdubers]

I have a 300 litre (DT) that has been running for aprox 6 months now

I was battling what appeared to be a dino issue but after manually removing it several times it now seems to be ok.

However since the dino’s have gone I have been having issues with black sand. I am unsure if it is actually cyno as it is jet black. Manual removal just means that it will come back the next day.

I was wondering if it could be Spirulina since it is so black? If it is Spirulina is that as dangerous as cyno? It seems like its harder to get rid of?

I plan to buy some peroxide to do a test but in the mean time what do you guys think it looks like from the pics?

My nitrate levels are testing just over 0 on API. I haven’t yet got a phosphate tester as I am saving up for the Hanna ULR Phosphorus tester.

Thank you for the help

 

[vetteguy53081]

Appears to be diatoms and detritus
Simply siphon up

 

[vdubers]

Appears to be diatoms and detritus
Simply siphon up

Thanks for your reply. I hope it is just diatoms. It is jet black though and when I had them at the very start they were more brownish.

 

[vetteguy53081]

Thanks for your reply. I hope it is just diatoms. It is jet black though and when I had them at the very start they were more brownish.

It will be darker with lower intensity lighting

 

[vdubers]

It will be darker with lower intensity lighting

Thanks fingers crossed it is just diatomes. When I syphon it comes up in mats and is stuck to the sand. Hoping it just works itself out and goes away by itself :).