Chaeto still green after 2 weeks dosing vibrant

[Danmuges]

I've currently just finished week 2 of dosing vibrant and the bits of chaeto that were left in the sump are still perfectly healthy and green. Does this mean I'm not dosing enough? My tank is around 105 gallons total volume and I've been dosing 11 ml each week as per instructions.
At what point would the chaeto in refugium typically start to die off after dosing this?

 

[swiss2]

Wait, why are you trying to kill the Chaeto in your refugium?

 

[Bj’s Reef]

Yes why are you trying to kill it. Most of us are trying to grow it.

 

[Mikedawg]

I doubt he's trying to purposely kill Chaeto, but has read that Vibrant will do so and wants to stop dosing before that happens

 

[Danmuges]

No, not trying to kill it. I removed before I started dosing and there was a tiny bit that got left behind. So I just left it there.