Tightening up Alternator Belt??

[79BIG10]

Okay here's my dilemma- I've got a chrome alternator and a chrome alternator bracket and I'm having trouble getting the belt tight enough. Just when I get it tight as I can it loosens up. There's no movement in the alternator itself (used pencil mark to make sure) after the engine has ran but the belt is loose. The belt has been replaced with a new one same size and still having issues. I can't use a prybar like on the old bracket that had a whole in the top where you can stick pry against. Also I've done as close as I can with the prybar against the water pump and still no luck. I've even used a strap wrench and pried and still loose. I'm at my wits end. Kevin Shortell once mentioned about a alternator tool that helped tighten the belt and he got it at AutoZone. I've been there and other places and no one has heard of it or carry it for rent or for sale. Anybody know what else I can do other than a serpentine system?