Originally Posted by fort384
Not time to panic yet - but don't dose the excel or comprehensive till the lights come back on. With no light, plants are not uptaking nutrients.
I'm not sure about not dosing excel. It's algaecidal properties might very well come from exposure and not be related to the photocycle. Because of this, dosing Excel in a blackout could boost the effects by further stressing the algae.
I think (based purely on speculation) that the half life of Excel in water is based on its breakdown and absorption by heterotrophic and chemoautotrophic bacteria. I just sent an inquiry to Seachem asking them about this.
But yea, ditch the comprehensive dosing.