no real build thread... but here is a pic of the sump room.
You can see the top where the water is coming from the main tank. It can go to the right and the skimmer, or to the left and the water barrel.
When i want to do a change I turn off the left valve stopping the drain from going to the barrel. I then go to the barrel and turn off the black black valve, and the red one on. This will drain the water barrel into the sink. Once empty I turn off the red and on the black. And wait for the water to fill.
Once full, I add one fifty gallon bag of IO reef crystals (plus two cup) and wait for everything to test right.
Then I just turn the left valve back on.
Water change complete.
