Answer:

First, are you using stabilized chlorine (tablets or granular with stabilizer)? If so, you probably do not need to add cyanuric acid. If you are using liquid chlorine or calcium hypochlorite or another form of unstabilized chlorine then you would need to add enough stabilizer to get to 30 to 50 ppm. The amount needed varies depending on if you are using liquid or granular stabilizer. Consult the packaging for dosage information.