Prevent algae before it starts with Back-Up® 2. This highly effective formula prevents wide variety of algae growth. It's stable in sunlight and will not evaporate. The activity of this product increases as water temperature rises, which is when you need protection the most. Back Up® 2 has a powerful surfactant/wetting agent, which makes it able to work in the tiny cracks and crevices where algae starts. This product will not affect pH levels and is non-staining.
Add 32 fl oz per 25,000 gallons of water.
Add 1 fl oz per 5,000 gallons of water per week, or 2 fl oz per 5,0000 gallons of water every 2 weeks.
Add 4 fl oz per 5,000 gallons of water for every week unattended.