I would not buy it online. If it's the thin plastic it will bow outward. I used something similar when transporting a tank. Could only fill each tote half way without it basically losing its shape.
Yea I would imagine it wouldn't be an issue if you can reinforce it. Not sure if it would necessarily leak chemicals over time though. Maybe someone else have an idea on that?
Ok cool. I did some research online and lots of people used Rubbermaid brute and roughneck for mixing and freshwater storage one dude even made a video for a ato siphon break and had a Rubbermaid brute hooked to it
Those will leach into your water. Look for pet food storage containers. I have one with a screw on lid like the old salt buckets. Its awesome. Sturdy and holds 10-12 gallons.