Hi I am getting very discouraged over our aquarium. I can not get the water to stabilize.
It is a new tank started with a cycle starter before adding fish, water was perfect added fish fed them too much got high amonia, did a water change fixed the amonia problem now my nitrate is 5.0 my nitrite is .50 and my ph keeps going up and down. I have tried nitraZorb, aquarium salt, I put in cycle by nutrafin every day for a week and the nitrate and nitrite stay the same. So now I'm putting in biozyme every day for 3 days now and still the nitrate and the nitrite is still the same. We have lost 7 fish now and I need help so we don't lose any more.

How big of an aquarium are we talking about?

We have a 55 gal tank

I should have asked if it was freshwater or saltwater. I know there's salt in water conditioner so I didn't want to assume that you do have a saltwater tank. Any plants? Plants will do that to the levels

Freshwater

Well if you have any plants that might be your problem. I'm not an expert but I had issues with my fish tank and I had live plants in it. I decided just to take them out and I haven't had any problems since. If you don't have plants I would take a sample of water with you to a petstore and have them test it and help you figure things out. I know they're very helpful at petsmart if there's one near you

I've taken water samples every day for a week and they keep telling me to add cycle and I have been doing that but nothing has changed. I don't have any live plants

You are going to have water readings all over the place as your aquarium cycles - no worries there.
Use nothing but the product Cycle by Nutrafin.
You can discontinue all the other stuff and follow the directions on the Cycle bottle.
The tank is going to have to go through this process.
Your water readings are going to go up and down during this process so don't worry about that.
Not too much longer you should have readings something like ammonia 0ppm, nitrite 0ppm, and nitrate .5ppm or above.
The tank is cycling which is good, just drop down to only using the Cycle By Nutrafin as the bottle recommends.
Good luck.