Is it bad for shock to sit on the bottom of pool?

It depends on the type of shock you are using. Some types of shock, such as chlorine shock, can damage the pool liner if left in contact with it for an extended period of time. Other types of shock, such as non-chlorine shock, are less likely to cause damage. Always read the manufacturer's instructions before using any type of pool shock.

If you are using chlorine shock, it is important to circulate the pool water thoroughly after adding it to ensure that the shock is evenly distributed throughout the pool. You should also avoid leaving the shock in the pool for more than 24 hours. If you are using non-chlorine shock, you may be able to leave it in the pool for a longer period of time, but it is still important to read the manufacturer's instructions.