Tonight, for the first time since setting it up, I cleaned my new tank.
My new gravel siphon is awesome and did an excellent job. Strong sucking power meant none of the crud got backwashed into the tank. Of course, the bigger tank means more water to remove and to more water to add back. I didn’t let the water sit overnight to off-gas like I usually do. Just to do the 30% flush I needed three buckets of water. I did add some dechlorinator though. I’ll see how this water change goes, and if nothing disastrous happens, I’ll likely do the same procedure next time.