Cyano on the rocks...new bulb time?

[Stray32]

So almost overnight, I have nice looking purple cyano on some of my rocks, and it doesnt seem to be getting better. Phos and Nits are zero, flow hasn't changed, so I thought perhaps it may be ready to replace the bulbs, it's been a year.

Can old bulbs cause algae?

 

[Harry_Y]

I will get a Cyano outbreak when it is time to change out my GFO

You may have high phosphates, or something dead and rotting.

 

[Paul_N]

They say the bulbs tend to shift toward the red spectrum when they are at the end of their life. I don't know. I'm not a lighting expert. If your bulbs are right at a year, I would agree with Harry that it is most likely phosphates or some other nutrient issue. I have (2) T5 bulbs that I have had over a year and got them with a retro kit I got used and the guy said they were 6 months old, so that makes them 18 months old and no cyano. I just use for supplement though.

 

[Usefulidiot213]

Did you check to see if you have any missing fish? Might have lost one.

 

[Obsessed]

Yup old bulbs can cause it to break out, a buddy of mine was just talking about it and as soon as he changed to new bulbs it went away.

 

[Stray32]

All fish are accounted for, missing a few shrimp, but have been for months, so I suppose that could be it.

 

[beaslbob]

Try killing the lights for a few days.