Hi bellebrit,
Welcome to TFP. We sure do know the frutration and worry you are going through. Sooo many people are led the wrong direction for their pool care.
Just to mention, the TFPC method of pool care is Very different from what you have previously been told or what you will be told in the pool store.
Here is the difference between us and them. We think you, or anyone else should only add what is actually needed to the water.
The pool stores think you should add whatever the heck they can sell you with a high $ price tag attached to all that stuff.
The fact of the matter is, taking care of your pool is easy if you know what to do and the only way to do that is to be able to reliably test your water. Yourself.
Then only add what it needs. So, having a good quality test kit is critical.
Armed with a test kit and the knowledge that can be learned from these fine folks, you can expect the test kit to pay for itself in chemical savings the first month.
You are in good hands here, so relax and dont worry. Everything will be ok now.