After the algaecide is added, you should wait 15 to 20 minutes before going in. Be sure to test your water for chlorine and pH levels, so your pool or spa will be safe and comfortable for your users. Kem-Tek algaecides are not toxic to humans.
The Recommended Daily Allowance (RDA) of magnesium for young adults is around 400 mg/day for men and 310 mg/day for women. For adults over 30, the RDA is 420 mg/day for men and 320 mg/day for women.
Excessive use of magnesium supplements can be toxic. The upper limit -- the highest dose a person can take -- of magnesium supplements is: 65 mg/day for children ages 1-3. 110 mg/day for children ages 4-8. 350 mg/day for adults and children ages 9 and up.