Is This Cyano?

[Myanth]

I had a big problem in my 10 gallon once upon a time. Was using the DT's as well. I stopped and it went away, with some work. sucking it out with a small hose when doing water changes and shutting off water flow and using a stiff bottle bruch to wrap it up. (kind of like you would wrap spagetti around a fork). I have been told that it is full of PO4 - fertilizer for hiar algeas and cyano. I guess they put it in to prolong the life of the phyto.

Could be your issue. How old is the stuff?

Mike