I love watching my 150 gallon tank during water changes. As I add water back into the tank, the fish go crazy, swimming through the bubbles and schooling tightly. My gold barbs group together, swimming throughout the tank in a hug pack. Here are some shots of the tank during the refill that I liked:
I used to use Seachem Prime during all of my water changes. If you don’t use this stuff, start! It works wonderfully, and a single bottle lasts a long time. For my 150 gallon, because it is so large, I began using Seachem Safe. Safe is just a concentrated powder version of Seachem Prime. Both are phenomenal products that have made my water changes easier. They also can be used for emergency situations, like ammonia spikes.
When doing big water changes, it is much easier to be able to add the new water right to the tank from the faucet (as opposed to individually treating buckets and pouring them in). To the tank being filled, add enough Prime or Safe to treat the full volume of the tank, then refill the tank with tap water as usual. Of course, if your tap water isn’t acceptable for water changes, this process won’t work well for you.