Long time issues...

[FishyReef]

What type of GFO are you running?

I know for sure that I've asked this before, but are you absolutely certain the remaining spots are cyano and not red turf algae?

My best advice at this point is to just scoop out the area of sand where it keeps coming back. Maybe there is something decaying in the sand in that spot...

 

[Ulta]

absolutely certain the remaining spots are cyano and not red turf algae?

You would know red turf ;) it is like a wire brush>_<!

and wouldn't grow on sand

 

[mmfrock]

It's definately not red turf. It's not even like I could scoop it out, it looks like red sand granules. Not even like slime (ive have it look like sheets of slime before, but its not like that anymore). Just looks like someone threw cinnomon on my sand!

Anyways, my phosphate reactor has Phosban (by Two little Fishes) ferric oxide in it.

 

[FishyReef]

I think you might have won the battle against the cyano and what remains is something else. There is another thread in the algae section called something like "black crap on my sand" - he had a really hard time getting rid of it and it sounds similar to what you might be dealing with.

My only other thought/question is when you last changed your RO filters and Di cartridge? Might be silicates feeding it.

 

[mmfrock]

well...it's not "black crap" it's orange fairy dust! My RO filter hasnt been changed in about since last june (so i guess I can go ahead and do it) the only reason i havent is b/c the unit's directions said to change it when it becomes visibally dirty and its not. And my DI resin is color changing, so i change it when i need to based on the color, so thats an easy fix.

 

[FishyReef]

What you are describing sounds like diatoms, which I believe are fed by silicates, and from what I recall the presence of silicates mean you need to change out your filters and DI cartridge.