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.
Most backyard pools should operate with 2-4 ppm of free chlorine, although the use of mineral purifiers or ozonators can cut the chlorine demand in half. Trichlor tablets are used to maintain the normal daily operating level, and most pools will use 2-3 tablets per 10000 gallons, per week, to achieve proper levels.