Rocks turning black

[blufin]

I have a 90g aquarium that has been up for about 3 months or so. I have DIY led's over it, about 120w. My levels are stable and I see no problems with the water parameters. However, my rocks have turned a very dark green and almost black. When the soft corals move, I can see that rock is whiteish beneath it. The shadow cast by the softy prevents the rock from turning green, so I think this is a lighting issue.
The whites are on for about 6 hours, blues and UV for 10 hours, and I have no way to adjust/dim the lights. My rocks don't look anything like they should. Every other reef setup I see has mostly white rocks, coralline algae and such, but not dark green/black.

What gives?

 

[angelsbeamer]

That new of a tank could be an algae bloom. You said your parameters were stable but don't mention what the levels were and what you tested for? Coralline algae comes in different colors too.

 

[RalphsReef]

Any way to post pictures so we can get a better idea?

 

[blufin]

That new of a tank could be an algae bloom. You said your parameters were stable but don't mention what the levels were and what you tested for? Coralline algae comes in different colors too.

Any way to post pictures so we can get a better idea?

Alk 9.9 to low 10's
Calc 430
Nitrate trace
Phosphate trace
Salinity .023-.024
Temp 78-79

I can see what looks like a cyano bacteria on the rocks in one of these photos.

 

[eliramos]

that looks fine to me?

 

[GHill762]

^agreed.. unless you have a close-up, it looks normal from the pics.. the rock is aging and darkening up, is that what you're referring to? the fact that it's not bright white like dry rock?

 

[RalphsReef]

Looks normal to me as well.

 

[blufin]

The photo doesn't capture the color. It's about the color of the dried seaweed I feed the tangs.
I know it won't be bright white like new rock, but it seems darker than most reef setups I see here.

If you guys think its normal, I let it ride ans see what pans out.

 

[harryball69]

does look nice to me also...

 

[blufin]

does look nice to me also...

I've also got my sand starting to turn a rust brown. Looks like an excess nutrient problem and insufficient lighting. I gotta get this under control.

 

[GHill762]

I've also got my sand starting to turn a rust brown. Looks like an excess nutrient problem and insufficient lighting. I gotta get this under control.

Rust brown sand is almost always just diatoms.. Not a big deal, it'll pass.. Sometimes it's cyano and rarely something worse like dinos.. Post a pic..

 

[blufin]

Rust brown sand is almost always just diatoms.. Not a big deal, it'll pass.. Sometimes it's cyano and rarely something worse like dinos.. Post a pic..

Here's a few pics of what I'm talking about. I noticed my Purple Tang picking at the sand and when I looked closer, I saw that it was kinda furry and growing a short algae. It wasn't just a rust brown color on the sand I'm starting to get, I've also developed a red algae on the rocks. It isn't like a red slime algae that will blow off if you wave your hand over it. This takes a good scrubbing from a toothbrush to get it off.

Sorry for the sideways pictures. I don't know why Apple turned them on me.

 

[Devon93274]

My live rock has black growth as well. Anyone know what this is? Should I remove this rock before it spreads?

 

[Devon93274]

What is this?

 

[Qh2214]

Use "chemiclean" I had similar stuff but let mine get outta hand hoping it'd go away. Used that now my tanks never looked healthier

 

[cadmanof50s]

This looks like the beginning of an algae breakout. The first pic even looks a bit like Green Hair Algae starting.
The "black" growth could be dark cyano bacteria on the rocks. But could also be a dark strain of coraline algae. If it looks like it has a velvet sheen, than most likely cyano.
I would just be careful of not overfeeding, remove any excess waste and watch your phosphate and nitrate levels. Nutrient levels may be getting a little higher than your system can handle.


Every reef tank that I have started goes through cycles of "breakouts" of various organisms...especially within the first 6 to 8 months. During these phases its important to react and even more important not to over-react. It may be just a sign that you need to feed a little less generously and continue with your regular water changes and routine maintenance.

V.

 

[angelsbeamer]

Yep looks like an algae bloom.

 

[davidc]

Tanks only 3 mo. + old, it's still cycling/ maturing . Looks like cyano and will disappear with normal maintenance. Next waterchange, (soon) siphon it off the rocks and sand and continue to do so until it passes. What you are seeing is pretty normal on a new tank.
Keep a watch on your parameters and let it ride itself out.
P.s. Filled up and top off with RO/DI too right? Just checkin'

 

[mistynh]

I have this also but no way could I siphon it off rock it’s like painted black on rock. For a year it was light purple now it’s black . I think it’s over nutrients so I’ll work on that.

 

[mistynh]

I can’t get a good pic. I have so many air bubbles floating around