don't feel to bad, you are not the only person that I have helped that has not done a good cleaning on their tanks.. They have water issues like you do and that keeps them from proporley cleaning the tank.. but in the long/short run, the fish get sick, some even die before they realize what is going on..somewhat like what U are going through now..
Stress Zyme is really good in your tank right now as it does help nutrilize the Ammonia and high nitrites, nitrates that I am sure you are having.. See this on Stress Zyme..http://www.drsfostersmith.com/pic/article.cfm?acatid=424&aid=845
Now you said you have lost fish when you did a what change.. You are using Stress coat and that should take care of any harmfull chemicals like chlorine and chloramines, plus any hard metals that are in the water.. NOW one thing that it may be is LOW or HIGH pH.. Any kind of a 3 degree difference in the pH on a change wil really do a number on your fish. Like death..
TAKE a sample of your TAP water to the fish store and tell them you need to know where your pH is.. Also take one from your tank to see what the differences are.. They wil be different.. Please invest in a pH test kit on the results of the test.. they come in Low pH 6.5 to 7.6 and high, 7.6 to 8.8?..
Do you use any buffers?? Salt is needed to insure the fish stay healthy..It also helps with breathing, disease and other ailments that affect fish.. GET some Aquarium salt, it is in a milk like carton..I dose at hafe strength. I tablespoon per 10 gal..This is enough to help the fish.. ONLY add in on a water change NOT on tappin off the tank from water evaperation...
The exchange water can sit for 30 min and should be ready to place into the tank then.. the Stress coat is instant but letting it sit for a short time is good to make sure it is mixed good.. I use a small water pump on my exchange water to make sure it is mixed well..Add in the salt at the same time...
Now how much of a water change are you doing??
To calculate how much YOUR TANK SIZE x .25%= Don't change out to much, like 50% as it can cause more problems later..
So this is what I need to know now..
What is the pH of your tank??
Other chemicals you add:
Size of tank..
Salt?? do you use it??
How much of a water change do, DID you do??



