Let's start with the basics. What testing kit do you have, and what does your water look like currently?
We'll also need to know all about your pool. Take a look at my signature below and see if you can get some of the key details (you don't necessarily need model numbers - but knowing your estimated pool volume, type of filter, etc.) into your signature so that we can provide you with help that is tailored to your particular pool. You can edit your signature here: Trouble Free Pool
After editing the signature, respond here with your particular problem and don't forget to check the "show signature" box underneath the response area.