What is this stuff its like a lair of red algae on my sand

[fishlover07]

What is this stuff its like a lair of red algae on my sand

 

[Sniperhank]

That is cyanobacteria. It comes from excess nutrients in the water and low flow. Basics for removal involve cutting back on feeding, larger water changes, and increasing flow. There should be an article about it in the articles section if I remember correctly.