Need help with algae in sand

[gab997s]

This showed up a couple weeks ago. Water changes every two weeks 50 gallons out of the 175 tank. Siphon sand when water changes and still around.

 

[oscarinw]

What kind of algae is it? It's hard to identify from the pictures. Look at methods to reduce your nutrient load such as reducing feeding, adding a sump with macro algae for nutrient export, chemical nutrient reduction such as carbon dosing in any of its forms, using GFO to reduce phosphates in the water and addressing water quality issues via more periodic water changes are all options at your disposal.
Good luck

 

[A1t2o]

If you have a skimmer, set it to run wetter for a while. It will pull out more crap while you are taking care of the source of the problem. Keep siphoning the algae out, and check on your lights. If coral growth slowed then there may be more nutrients for algae. Test your parameters and post it.

Also, try taking pictures with more of a daylight spectrum to get a better color representation and that should help us ID it.

 

[CedzAquAddictio]

How old is your tank? Diatoms, possibly???