Just put a new 20# bottle on 2 weeks ago. Checked for leaks and all was good I thought. Have added 40gal of beer to keezer since then but noticed bottle was down quite a bit. Dam it! Sure enough there was a leak at gasket between tank and regulator so got that fixed. Then noticed a slight metallic taste in an Amber that had been on tap prior to bottle change out. Ok was wondering what happened there. Not undrinkable but bad aftertaste. Kegged a pale ale Friday and now it has same off flavor. The uncarbonated pale was smooth and very tasty prior to carbonating. The CO2 tank is low enough that i am going to exchange it today. Anyone else ever get a bad tank? There is no other explaination for it i can find. No excessive foam or any other indication of an infection. No choice but to exchange where i live unless I drive 100 miles. Edit: aluminum tank not steel or stainless.