What is your parameters: pH, KH, GH?
Is the new water for change same temperature?
wow u went all out w/ the co2 system and chiller...I had aproblem keeping those little guys alive too and I thought about all of the money I was losing so I decided to throw a ton of money at the problem. To control the ph I bought ADA Amazonia II substrate which took my ph from 7.4 to 6.8. To keep an eye on it I bought a ph controller. Lost a bunch due to a malfunction on the timer for my CO2 which caused my ph to crash. My water temp was always high so I bought a chiller to keep it in the mid 70s. I also bought a RO/DI to deal with the other water issues. This also helped to bring my ph down. My co2 system also helps to keep it down. So, about $800 later, my baby CRS are doing well. From the 10 I originally purchased from a member here about 9 months ago I now have around 60.
I am sure that there are cheaper ways to deal with all of the issues associated with keeping CRS but this is the method that I used and it has worked for me.