Quartz sand showing black

[MeCasa]

The sand that is directly under my plant lights is getting black on top. No substrate under this sand, 4" of sand

The sand that is not getting so much light looks normal. I see no algae on plants, rocks etc.

No fish yet

What is that black? Removed it once (only on top) but it was black within 3 days. Looks like soot.



6" over, rock blocks lights, no black



Thanks

 

[Brian_Nano12g]

It's a sort of algae i believe. Not diatoms, which is brown.

I used to kill the black stuff off my sand by spot treating with h2o2. Just turn the filter or anything creating current while spot treating. The black stuff should fizz like crazy. Then turn red... Then die. Repeat process for another day or two.

 

[MeCasa]

Thanks Brian,

How do I get the Peroxide down to the black, the tank is a 150

I guess I could put it in a spray bottle and spray the floor

 

[Brian_Nano12g]

I use a syringe and get it real close.. slowly squirt it over that area. The h2o2 is heavier than water and will fall on the sand. Just shut off anything creating a current. I'd leave it off for 15 to 30 minutes.

Up to 2ml/G is considered generally safe. But you'll use much less in a 150g. Just attack the affected areas.

 

[MeCasa]

Thank you sir!