Mordalphus: Thanks, I hope they stop dying soon too.
Soothing_Shrimp: I hope so.
Dougolasjr and Rob: I used to have a billion shrimp and a filter that stopped working, so I was doing water changes with that frequency to keep things under control while I got a second filter going. Eventually the new filter was working fine but I just kept up the frequency of the changes for some reason (habit?). If something happened to the water source and there was a sudden drop in gh, then I agree, frequent water changes probably devastated my shrimp population because I was throwing out all of the mineral content. Now that I know that this was (probably) an issue with water hardness (and now that I have barely any shrimp left to make the water dirty), I am keeping an eye on the nitrates and I will only do water changes when I have to. I doubt I will need to do them very much at all for a while.
jczernia and rodcuda: I assume you mean that the substrate needs to be replaced, right? Is there something else I'd have to do? What are the signs that a tank needs to be completely overhauled?
I have ADA Aqua Soil Amazonia and it is currently keeping my pH amazingly stable. My plants are growing like gangbusters, there is algae for the shrimp to eat, and my bio filter is working very well. I am currently not having to fight to keep any of the parameters from swinging around, though I am adding minerals because my tap water is about 1 gh. Does ADA Amazonia naturally keep a gH of 5? Because otherwise I am having trouble coming up with reasons why I should throw my shrimp into an unstable new environment when things are already so shaky. Assuming I did redo the tank, what will be the difference between that and what I currently have? What is missing from my tank that should be changed?