Well. when ever i decide to by new rams. What would be the best way to acclimate them?
First of all, it helps if the LFS water and your water is not very different to begin with. But even if there is a bit of a difference, the drip method works well, in my experience.
Float the bag in the tank (for temp.) and set a large plastic cup filled with your tank water on the lamp above the tank, with a piece of airline tubing letting out drops of water into a bag (make a hole near the bottom of the cup). If you don't have a flat lamp above the tank, you can run a longer piece of airline tubing from the tank to a bucket below the tank, and put the bag inside the bucket. Once you start the siphon into the bucket (not the bag), you can tie a knot in the tubing so the water will then drip slowly into the bag. With either method, I'd let the amount of water in the bag double (you may have to remove some of the original water) and then test for pH and GH/KH. If the water still isn't the same on both of these params, remove half the water in the bag and do it again until it is. Set the drops so it takes about an hour or so for the water to double, at least the first time -- so it really gives them a lot of time to acclimate. Also make sure the bag doesn't cool off if you are using the bucket method (you can add warmer water into the bucket around the bag).
My LFS has water that isn't very different from my tanks, so I don't really know what the limit is on how different the water can be for rams. It usually only takes me 1.5-2 hours to acclimate a new fish. But I've never lost a new fish using this acclimation method.
I also have another theory on why rams die like that -- but only if your tank water is more basic than the water they came in. Rams are VERY sensitive to ammonia, and the higher the pH, the more toxic the ammonia is. So even with the smallest amount of ammonia in your tank, if your pH was more than about 6.8, the toxic effects (maybe along with the medicine, ich, etc.) could have affected their gills. Here's an interesting link:
http://www.thekrib.com/Chemistry/ammonia-discussions.html
Good luck! Rams are such gorgeous, interesting little fish -- I hope you get a chance to try again. Mine are breeding, but I've only taken out one batch of eggs so far -- and that's when I learned about the high pH/toxic ammonia effect. (I left some baby food in too long, and my water pH is pretty high for ram fry at 6.8, so I lost them all.)
good luck!