GETTING STARTED OPENING UP YOUR POOL
The first thing to do is take an inventory of all supplies on hand. You will need sodium bicarbonate (to adjust TOTAL ALKALINITY), sodium carbonate (soda ash) or acid to adjust the pH of the water, chlorine (calcium hypochlorite liquid chlorine 10% or more, or lithium hypochlorite), chlorine tablets (1", 3", or sticks), stabilizer or conditioner (they are both cyanuric acid), and cleaning supplies (brushes, telepoles, cleaning solutions, etc.). By doing this first you will cut your trips to the pool store in half. Most of the chemicals are included in spring start up kits available through many mail order companies or at your local pool store.
If you lower your pool water for the winter, start off by filling the pool. Always fill on the deep end of the pool, being careful not to allow water to run from shallow to deep end. This will help prevent any staining caused by iron, copper, or manganese in the pool water. It is also a good idea to add a quart of a chelating chemical (stain preventative) to the water to help prevent staining. When filling the pool do not shut off the water before the pool is finished filling. This is especially important on gunite (plaster) pools since the water may leave a bathtub ring at a level other than operating level.
After the pool is full it is time to remove the winter cover. This is a bit tricky if you have a solid cover so if you can get some people together to help I would strongly recommend it. Remove any water that has accumulated on top of the cover. Begin by starting at the deep end and pulling the cover back toward the shallow end. In the event someone should fall in they are better off in the shallow end.
Next pull a sample of pool water from the deep end of the pool. You should dip a PLASTIC container at least elbow deep. Always use plastic or acrylic (shatter proof) containers around the pool. Test the sample for total alkalinity, pH, hardness, stabilizer, and chlorine. Yes, chlorine. You would be surprised at how much chlorine remains in some pools after a long winter. If you can perform only two or three of the tests, take your water to the local pool store for full analysis. This is perhaps the most important step in starting the pool since properly balanced water will make the job of cleaning and clearing you pool much easier. Think of it as checking the car before a trip around the United States. You wouldn't start out a quart low on oil.