I had the really bad heartburn\acid thing going on after about of month or so on Tren.
This combo pretty much cleared it up. I still have to occasionally pop a 20mg Pepcid (which totally clears it up), but not very often. Prior to this I was downing Tums and all sorts of stuff trying to deal with it.
1: Saccharomyces Boulardii
I got this tip from a mod on Evo. Apparently Tren really jacks up your gut bacteria, and this is a form of probiotic that actually works. You need to find it somewhere where it's refrigerated (Health Food Store\Whole Foods). This helped me more than anything.
2: Papaya Enzymes
My wife gave me this tip (major health nut). They really help in digestion period, are cheap, and actually taste really delicious. Pop like 3-4 after each meal.
3: Apple Cider Vinegar
Good for you all around. Have to get the organic stuff like Braggs. A few teaspoons in some water a couple times a day does the trick.
Anyway, this "stack" has me pretty much heartburn free on currently 700mgs Tren-A\Week, and previously on 800mgs of Tren-E\Week. Prior to this I was waking up 4-5 times a night pounding Tums because of the acid in my throat.
Good luck, peace.