I currently have a Aqueon HOB overflow on my tank. It always starts up right away. I did flood my basement though due to stupidity. I shut the return pump off and took the inside overflow box off without breaking the siphon on the utube. We'll the uTube kept siphoning and there went 2 gallons or so.

My other complaint about them is that they are noisey. You have to build stand pipes for them. Also, the clear boxes get horribly dirty. The only way to clean them is to soak it in vinegar. Go with a black box version.

I am using a 10 gallon rubbermaid to mix salt water in. It's works really well. Although, it does flex a lot.