What chemicals are used to start up pool for the second season?

1. Chlorine shock: This is a high concentration of chlorine used to kill bacteria and algae in the pool. It should be added before any other chemicals are added.

2. pH balancers: pH is the measure of acidity or alkalinity in the water. It should be kept between 7.2 and 7.8 for most pools. pH balancers can be added to adjust the pH level if it is too high or too low.

3. Alkalinity increasers or reducers: Alkalinity is a measure of the bicarbonate and carbonate ions in the water. It helps to stabilize the pH level and protects the pool from corrosion. Alkalinity increasers or reducers can be added to adjust the alkalinity level if it is too low or too high.

4. Calcium hardness increasers or reducers: Calcium hardness is a measure of the dissolved calcium in the water. It helps to prevent corrosion of the pool equipment and reduces the risk of scaling. Calcium hardness increasers or reducers can be added to adjust the calcium hardness level if it is too low or too high.

5. Stabilizer: Stabilizer helps to prevent chlorine from being broken down by the sun's UV rays. It should be added once at the beginning of the season and then reapplied every few months as needed.

6. Algaecide: Algaecide helps to prevent algae growth. It should be added at the beginning of the season and then reapplied every few weeks as needed.

Note: The specific chemicals and dosages needed will vary depending on the size and type of pool, as well as the local climate. It is always a good idea to consult with a pool professional to get the best advice on how to start up your pool for the second season.