Understanding the Risks: Algae Growth in Harvested Rainwater

---

One of the most prevalent challenges in rainwater harvesting systems is algae growth. Algae thrive in environments where sunlight can penetrate and initiate photosynthesis. An algae-infested tank does not just affect the water quality by imparting a foul smell; it also turns your tank into a thriving ecosystem for various forms of wildlife. 

The Solution: Smart Practices and Monthly Maintenance
A comprehensive approach towards maintenance and preventive measures is crucial to mitigate these issues. Here's how you can maintain the purity of your harvested rainwater:

Tank Covers: A Critical Choice
Whether you're using Doughboy or Galvanized Steel tanks, the type of cover you choose plays a significant role in preventing algae growth. Avoid being misled by "Premium" cover labels; what you need is a 99% Blackout cover. Despite the durability of premium covers, they fail to block sufficient sunlight, paving the way for algae blooms. Opt for a 99% Blackout cover to effectively keep sunlight and, consequently, algae at bay.

 Monthly Maintenance Duties 
  Regular maintenance is your best defense against contaminants. Here's a simple yet effective monthly checklist:

•     Add 2 oz of bleach for every 1,000 gallons of water. This will help kill existing algae and prevent future growth.
•     Ensure all wet piping is drained to avoid water stagnation.
•     Keep your roof and gutters clean to prevent debris from contaminating your water supply.
•     Cover clear filter housings with a wool sock to block light penetration.
•     For poly tanks, consider painting them to block out light.

PVC Piping Maintenance
Exposed PVC piping between the tank and your house can be a conduit for algae growth if not properly managed. To combat this, you have two options: painting the PVC pipes with a reflective or light-blocking paint or burying them. Both methods are effective in preventing algae by blocking or minimizing sunlight exposure.

By implementing these practices, you'll maintain the health and cleanliness of your water and contribute to the sustainability and efficiency of your rainwater harvesting system.


The Bottom Line
If we seek to make a difference in the quality of our lives and the environment, we must shift our actions and mindset. This holds particularly true for rainwater harvesters in Hawai'i, who play a pivotal role in managing and maintaining the purity of their water supply. Rainwater harvesting is not just about collecting water; it's about ensuring that the water we collect is safe and healthy for all purposes, whether drinking, cooking, or bathing. After all, the water that touches our skin or that we ingest directly impacts our health.