Something growing rapidly, please help

Not sure what's going on...tank is nearing end of cycle, as it appears the nitrite and nitrates are finally coming down...today is day 37.

This rust colored algae or whatever was not visible on the base rock this morning... but it is as of late this afternoon. It is appearing directly below and under some donated live rock that was placed in my tank late Friday but pulled out Sunday and Monday so that's 5 days for growth.



Moreover, please also note that the small live rock with coraline and what I believe to be cinnamon zoanthids... it appears as though the rust colored algae is overrunning the coraline. The coraline had none of this visible when placed on Friday (2nd picture down)... this is what it looks like now:



Here is the original specimen of coraline and possible zoanthids as received Friday, 11/4. The 'finger' shaped rock was removed 2-days ago so not shown above photo but base rock that supported 'finger' specimen now has rust color growing on it. Discoloration seems to also be growing on rear tank wall but very hard to photograph.



Any idea what this stuff is and how to get rid of it? (New tank cycle may be near end of cycle - no fish, but have 4-5 very small feather dusters that came with a substrate donation...from different tank than the coraline and rust colored algae).

 

diatoms probably, hope that hammer makes it if it was in there when you weren't finished with your cycle. It happens with most new tanks.

 

Yes, that hammerhead is nice... but really more worried about the coraline because I can get a fist sized hammerhead for $10.

Will a clean-up crew of some sort help?

 

If it is diatoms, it should die off on its own pretty quick. When my tank was finishing its cycle, had a diatom bloom that lasted not quite 3 days. Once it uses up the silicates in the tank it should die off. As long as you are using RO/DI water, it shouldn't be anything to worry about.

 

Good news.... using ro/di. So why is this making me so nervous? ..seeing it cover over that awesome (irreplaceable) coraline specimen I think. :-/

But, sounds like you are not sure that these are diatoms.

Could this be something else?

 

Forgot to mention that the hammerhead is doing especially well and seems quite happy... seems to be growing since being placed late Friday.

I'm told by a marine biologist that they actually like nitrites...which is good as they were exceptionally high (off the Hagen and API test charts) when he was planted.

 

Appears to be diatoms to me, as well.

Diatoms are a natural occurance during or shortly after the cycle and are generally short-lived, depending on your water source.

 

I had a couple of pieces of LR that I used to seed the base rock. It had really good coralline growth on it. Some of the diatoms got on them, but no worries. The diatoms weren't around long enough to hurt it. Like you said makes you nervous, but sounds to me like it shouldn't be anything to worry about.

 

Don't be nervous! Congratulations! Your tank is finishing cycling. You did something right I would be nervous if I didn't have diatoms after cycling..

 

I needed to hear this about the coraline. Thank you.