Nick Wise wrote:
A blackout does no good if your tank's nutrients are still out of
balance. You need to get those in line, or the algae will never go
away. You have to treat the source.

I agree with this. I would've personally done some scrubbing on more built
areas, done a major water change and then tried the blackout. Probably
for longer than 3 days, whilst not feeding the fish. They'll pick up
any loose particles.


Always worked for me.