MotoroLVR, welcome to Tropical Fish Keeping forum.
I won't repeat what's been said. I will suggest though that daily water changes be around 50% if ammonia or nitrite is above .25, and use a conditioner that detoxifies ammonia and nitrite. There are two I am aware of that do both, Prime (made by Seachem) and Ultimate (made by Aquarium Solutions). If you have live plants, they will help enormously, as they grab a lot of ammonia (as ammonium). Also, seeding the tank with live bacteria from an established tank, or using a biological supplement also helps, provided it is 100% bacteria and not a bunch of chemicals. Seachem make Stability which is good, and Tetra make SafeStart; both are 100% live bacteria and they absolutely do work to establish the bacteria colony faster.
I am concerned about your mention of buffering the pH at 7 though, and would appreciate if you could explain what this refers to. The pH of your tap water will help, and how you are "buffering' it. There are good and bad ways (to the fish).