Maybe sounds a bit weird (but most here would understand
)... I actually really look forward to this once a month exercise.
First step, and most important, I need to plan for a day my wife is going to be at work. -
3 days ago mixed 25 gallons of water and has been well areoated and brought up to right temp.
Fish fed couple of hours earlier, so they should not get overly stressed by event - although they should be pretty used to by now.
I then I do all my basic water tests to see if anything needs special attention.
First I do all the glass cleaning I need to, then drain out 25 gallons from thank. - while doing do, I vacuum up all the detrius from LR I can without disturbing corals (and getting any patches of red slime which I have been battling with of late) - actually it is almost gone from earlier vacuuming - also vacuum sand I can get to.
Then pull out skimmer from sump and give it a good cleaning in and out. - esp. injector port and air port.
With turky baster I clean out any gunk accumulated on sump bottom.
I clean and replace the small overflow type filter on my sump where I alternatly run a "Poly Filter" and carbon from.
Then it is put back together in reverse order.
Usually takes only about 20-30 minutes to do this...and the tank (and myself) always seems much happier when finished.
Ok, having written about it, am anxious to get started...am off to do...
Tank Cleaning Day! 
and yes those are my zoa's in that pic.
