It's definitely the set screws, I did a "scotch tape test" as soon as I found out it was leaking.

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السلام عليكم - الفدائي المرملة

Those tanks are notorious for leaks and poorly tightened set screws. I've had three in one day,, the first two went right back to tthe vendor.
Anyways, try tightening the set screws or even teflon taping them and re installing them. Just remembr that those set screw stop your tank from becomeing a missile when you are unsceewwwing it under pressure. Make sure to tighten them up after removing them.

Dan

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