switching saltwater back to freshwater, help

I agree with the suggestions of cycling the tank. You also need to test the water. By just adding fish and having them die, you are not getting any information on why they might by dying.
 
But if you are just adding the fish to the tank water with out a proper acclimation this is stressing the fish a lot, especially since the water qualities are obviously way different. Floating the bag for 25 moniutes accomplishes nothing. A true acclimation can take an hour depending on the fish and has little to do with matching temperatures.

In my tank I place the new fish in a small container (tupperware etc...) with the fish store water. I then start adding water from the tank into the tupperware. A little at a time over the next hour to 2 hours. This slowly gets the fish used to a change in water quality. When the container starts gettign full I take some water out of it and eventually the tupperware will be mostly filled with tank water. Then scoop the fish out with a net and add it to the tank.

You still haven't mentioned what the water source is and what chemicals you are adding to the water.
 
bannershuffle said:
my source is tap water (which ive used for 5 years now w/ no problem)

and i am adding nothing to the water


There's your problem, right there. It doesnt matter if you've been using it for 5 years, the properties of that water may have changed. I honestly dont believe that you've been using that same water for 5 years without any problems or fish dying. That must be the cleanest tap water in the country.

At the very least, you will want to declorinate that water, once your tank is filled. There are many brands out there, but I prefer Prime by Sea-chem. It not only removes chlorine, but also cloramine, and ammonia.

And again...you need to cycle this tank. Get it set up, and let it run for 4-6 weeks.
 
I think you should quit killin the fish.I learned the hard way that in any aquarium related hobby the only way to actually have a healthy,thriving tank evironment is Patience and Research.There are tons of very informative posts on this site on how to start both freshwater and marine tanks.
 
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