Starting A New Tank, But Old Tank Rock Has Cyno — Can I Use In New Tank Sump?

[JumboShrimp]

Knowing that I’m setting up a new 180 gallon tank, I admit to slacking-off on my current tank. Now there is a bad Cyanobacteria outbreak. I would never just use ‘Cyno-rock’ “as-is” to jump start the cycle in my new tank, by putting it into the new DT, but could I scrub the Cyno-rock with a brush in a bucket of saltwater (to preserve the beneficial bacteria) and use it in a dark sump under the new tank? I hope my question makes sense. Thanks.

 

[KingTideCorals]

You’d want to ensure you put that rock through a cycle process again in a separate container (rubber bin) to monitor, test, and keep an eye on it.

There’s a great BRS video on this exact thing about recycling old rock for tanks on their YouTube !

 

[JumboShrimp]

Thanks. I was hoping not to have to recycle, but I suspected taking a short-cut might be a bad idea. I will watch the video— it’s probably been a long time since I’ve seen it.

 

[Beau_B]

I had a similar situation and used chemiclean to eliminate the cyano. Since the new tank didn’t have the same nutrient issues it worked well.

Alternatively if you put the rocks in a bin without light for a couple weeks the cyano should die out too.

 

[JumboShrimp]

That’s kind of what I was thinking/hoping. Starve out the Cyno-rocks somehow in a dark bucket, then when the rocks get into the new tank with perfectly clean new water (I just got a 6-stage RO/DI unit) there should not be the conditions for a new outbreak. (?)

 

[ScottB]

IMO, a good scrub and salt water rinse is all you need to do. Cyanobacteria is in every live salt water system. We don't see it until we create an environment that allows it to outcompete other bacterial and algal forms. It is not like introducing aiptasia or bryopsis to a new system.

Good luck on the new build!

 

[JumboShrimp]

... somewhat to the points being made, it just dawned on me that the Cyno on the rocks in the DT is bad, but there is none whatsoever on the rocks in the sump; same water system, but no light.