Test kits are normally only good for 2 years. You need a new one. I hope one of the smaller mom and pop shops in your area is able to provide good informed advice to you. Even if they don't have a wide selection of fish, they may be willing to order in whatever you are looking for. The mom and pop shops that are really good will remember what kind of fish you keep, and will ask you what size tank, and what fish you currently have before making suggestions. I find it's best to go on fact finding missions, before buying. I go in with paper and pen, write down everything I have an interest in , ask questions from the people who work there, and then go home. I then take everything I had questions on and research them. I check the information the clerk gave me against my research, and make a decision based on a wider amount of knowledge. Sometimes the clerks know nothing about some of the fish, as they are something new or not carried on a regular basis. One thing you will want to do while your tank is cycling is decide what fish you want to keep as the fully stocked tank. Research those fish and there needs. The tetra, and corry you had both do much better in groups of 5 or more. The next thing to plan is in what order to add new fish once your tank has cycled. You will need to add just a few at a time in order to keep mini cycles to a minimum. Don't worry about all the things you may or may not have done wrong, we all learn from the mistakes. Now that you have found a source of information that is not concerned with selling you something you will find the advice is usually water changes, and routine maintenece. The only time the advice that you get will cost you anything is if you have an ilness that requires medication. I hope you enjoy the hobby once your tank is cycled.
