While spaying is traditionally recommended for kitties between 4 and 6 months of age, spaying as young as 8 weeks old is considered safe, according to Cat Channel.
The national drinking water standards state that the maximum residual amount of chlorine is 4 mg/L. Untill recently the USA used chlorine gas extensively for wastewater treatment. Today, the use of chlorine has been forced back.
According to the Pool and Spa website, you add 2.5 ounces of the chlorine for every 10,000 gallons of water. This is generally the standard with most chlorine manufacturers, but reading the label of the brand you have purchased is suggested, in case of slight differences.