What in the world is this ?

[agonzo2008]

It’s been in my tank for about 6 weeks . It comes and goes with lights on. It’s like brownish reddish in color and is on my sand bed and starting to get on my rocks . As I do water changes I syphon it out and it comes back. I’m currently using vibrant for about 4 weeks and it’s still in my tank. Is it diatoms, Dino , or algae ? What can I get or what can I do to get rid of it ? Thanks in advance

 

[35ppt]

It's always best to grab a cheap microscope and make an ID, without that people are just guessing. Coming and going with the lights makes me think dinos but I see your rocks are still maturing so it could also just be normal diatom bloom. What are your No3 and Po4 readings?

 

[agonzo2008]

My phosphate is at zero and nitrates are about 10 ppm. My tank has been running for 13 months now and i recently bought a uv sterilizer but so far all that helps is me siphoning water through a sock and catching the algae.