You don't have to worry about CH being too low in a vinyl pool anyway. CH being too low is only important in plaster/gunnite pools to keep the water from leaching calcium out of the concrete. In a vinly pool, there is no calcium in the pool surface to protect.

If your CH gets too high, on the other hand, it can cause problems with milky water.

Janet

Edit: LIsa and I were apparently typing at the same time--she's quicker than me tonight!!