Complete H20 change-scrape algae week before?

[BradR]

Changing all the water in a 180 for the first time in 3 yrs.
There's minimal coral in it but about 300# of live rock.
Lots of algae. Can't even see into the tank.
Should I scrape the glass and rock right before the water change or a couple days before so the DOC's are in the water?
Thanks!

[wrott]

I would scrape before you do it, it probably won't matter if it's days or hours before.
There could be lots of phosphate bound in the rock. It will leach out even w/ new water and algae will be back.
You could use a couple of phosban reactors or cook the rock for a few months.

[Rewd]

Why are you changing all the water?

[BradR]

Ok, will scrap just before. Changing all the water as it's been 3 years and it's nasty. No live animals except a few scarlet hermits. This should make the biggest change vs two 90gallon changes.