Red sand

[g_acosta_02]

Can anyone tell me what is this on my sand? Have tried everything and nothing seems to work. From lights out to barely feeding to chemiclean , vibrant even siphoning the sand blowing the sand and it keeps coming back.
So I ask myself does the sand in the aquarium have to get replaced? Don’t know what to do any more

 

[Dan_P]

Can anyone tell me what is this on my sand? Have tried everything and nothing seems to work. From lights out to barely feeding to chemiclean , vibrant even siphoning the sand blowing the sand and it keeps coming back.
So I ask myself does the sand in the aquarium have to get replaced? Don’t know what to do any more

Can you share a photo of the sand under white light?