What a mess?

[Hookman]

How is everyone. I used qickrete brand playsand when I set up my tank 5 months ago. The brown algae on the sand in the less circulated areas looks terrible. Could this be from this type of sand, or using bottled spring water for top off. I thought it was 100% silica, but it say's nothing on the bag. I was also wondering if it is accumulation of waste because I don't have all my LR, so it cannot keep up. Any help is appreciated, If someone really thinks it is the sand, I will replace it with some other kind. Thanks for your help!
P.S. There also looks like there is some almost black velvet looking algae growing on one of the rocks.

 

[Michel]

IMO it's the spring water ! What is in that water ???? Everything except chlorine so...
If you go with bottled water go with distilled
As for the algea from your description it would eiter a diatom (because of the water) or cyano (not an algea but a bacteria) due to poor circulation or too much nutrient !

 

[fishfreek]

The brown algae on the sand in the less circulated areas looks terrible.

Increase the water circulation in those areas and it will probably help a great deal.

 

[MACATUA]

My thoughts exactly, just point a powerhead wherever you see these spots should help.