Diatoms or cyano?

[lmforbis]

I upgraded to a 125 about a month ago. Everything from my 55 (rock, sand, water, sump and livestock) was moved to the new tank. I had a mini cycle that lasted a few days. The last week to 10 days I have had a brownish something (I figure either diatoms or cyano) growing on my sand. Every morning it is completely gone then when the lights come on it comes back. I have a sizable CUC including a sea hare that keep things in pretty good shape most of the time. I am leaning toward diatoms because it isn't on the rocks and not particularly slimy looking.

What do you think?

 

[reefkeeperZ]

probably diatoms. red slime will not fade at lights out, diatoms will. not surprising since you totally restet the tank and added more sand so there is fresh sil;icates for them to feed on.

 

[bang guy]

I disagree with Reefkpr (could be the first time). In my experience Cyano decreases significantly and rapidly when it's dark while Diatoms hang in there.

 

[reefkeeperZ]

doh, you're right I had my thinking backwards, don't know why I flipped that. Sorry OP, and thanks bang guy for straightening me out I'll blame it on being tired... or something lol

I definitely shouldn't have flipped it. I know from past experience that swapping old sand into a new tank disturbs the layers of microfauna and exposes trapped nutrients that were unavailable before due to flow restrictions through the bed and cyano bursts happen as the "new" sand bed re-matures and balances itself out again.

 

[lmforbis]

That makes sense, especially since it isn't on the rocks. Changing the flow has always worked in the past but it isn't touching this, just causes a sand storm. So it should clear on its own as the sand bed matures?

 

[reefkeeperZ]

if you keep siphoning it out the thickest stuff, and keep the sand bed stirred it should eventually, Unfortunately cyano can take several months to run its course, depending of course, on the amount of nutrients there are to be consumed.

 

[CarlL]

You can also try a sand sifting goby worked wonders in my 125.

 

[beaslbob]

you already have a big hint in that it is almost gone in the morning.

IMHO I would reduce lighting and feeding (including stopping both for a few days) until it goes away. then adjust both so it stays away.

IMHO you just need to rebalance the tank. It should not be hard as it is almost there already.


my .02