Hello, and Help!!

[TinaS]

I have a fish tank that keeps getting out of wack!!
I tested the water and the test are not good, I have lost 1 fish that I know of.
So on the water test it comes out:
Nitrate - Unsafe
Nitrate - safe
Total Hardness - Very hard
Total Alkalinity - low
Ph - acidic

I have done a 25% water change, and all seemed well, but then the fish started acting odd again, to tested it and those were the results.
So my question is how to get the tank happy and how to keep it happy.. Please help. I know people that just feed and enjoy their fish, mine is a constant battle.

 

[Aiken Drum]

A few questions to start with.

What do you know about the nitrogen cycle?

How long have you had the tank? How big is it? How many fish? What types etc?

How did you cycle the tank? Did you cycle the tank before getting fish (fishless)? If so what did you do precisely? Are you now cycling the tank with fish in it? Or is this the first time you have heard about cycling a tank?

What test kit are you using? Do you know what the numbers are alongside those test results rather than safe/ unsafe etc? You havent mentioned the most important parameter. Ammonia. Do you know your ammonia?

What is you normal water change schedule? How much, how often?

You arent cycled. Your tank isnt capable of keeping the water safe. There are processes you need to follow to safely cycle a tank over time while keeping fish alive. We can get more into that once we know a little more about whats going on.