I was wondering how long can u keep water for. For example if i were to keep a 40 gallon barrel of water? Will water go bad? What if its constantly moving?
If you are going to keep a barrel of water to use for water changes. I would keep it covered and an airstone running in to keep it well aerated.Also a heater to bring it to the correct temp.
This si what I do, I have 2 55 gallon plastic drums. I have a maxi jet 1200 in one of them and huge air stones in the other, Irun them constantly, if I let it sit for a day without movement, i get algea fast. Keep the water moving.