Is This Cyano?

[Funky_Fish14]

Originally Posted by Ruth

I have found that it seems to consume and thrive on PO4 and because it consumes it your tests will still come out at normal.

As Ruth stated, this may be the reason why you had undetectable PO4.

I've also read some interesting papers suggesting PO4 building up in the rocks, so you may want to try Ruth's suggestion of soaking one in a bucket, swishing it around alot, then testing the water.

I've seen cyano show up quite late in upgrades aswell. Whether it has been a new tank, or an upgrade to a larger system from smaller mature systems, I've always had it show up sooner or later.

Good luck getting rid of it! Im sure it will go as it came, mine has always done so after a couple months of battling it.

Chris