whats the process for a 3day blackout?

Prune snip, clean, fluff, preen, and then clean filters, tubes etc.
Then do a water change, 50% or so..........
Add KNO3/PO4/GH(no traces)
Then turn off CO2, light.
Add a bit more current to the surface.

Cover tank with 2 layers of trash bags etc.

Wait 3 days

Remove bags, turn light/CO2 back on.
Do another 50% water change.

You can add some Excel as well after the water changes.

You can also and likely should do 2-3x a week 50% Water changes followed by Excel, revamp and look at the CO2 much more and watch plants for new growth.

Keep up on things from then on. after a 1-3 weeks of hard work, you likely can back off and relax.

Regards,
Tom Barr

 

Yes, for the most part you got everything right.
Fluffing a tank means just sloshing the water around and flicking the plant leaves underwater good to get any dust that settles or dead leaves off, then net them out etc or siphon out.

Preening-> see birds and their feathers, they clean them individually and meticulously. Same deal with plant leaves etc.

Cleaning the filter just means rinsing the media etc with warm tap water good, get the dirt out, use those long wire brushes to clean out the tubes etc, add fresh floss etc.

Regards,
Tom Barr