Rain collection tips
The only reason you would want to filter it is if you were planning on using it for cooking or drinking. Chlorine once a month is quite sufficient if you are using it for toilets and showers.
Rain collection is practiced for thousands of years...nothing new here.
Here are some tips;
1. Install a "rain delay" at the gutter intake. This will prevent collecting the first 10 minutes of rain water thus allowing the washing of the roof from debris, bird feces, moscitos, dust, pollution etc.
2. The systern MUST be
totally sealed from sunlight and crawlers such as lizards, snakes, frogs etc. Dead animals will decay causing bad odor. The block of sunlight stops the algae grow in the systern. A tablet of chlorine is essential to kill all remaining bacteria.
3. Every six months it is recommended to clean & disinfect the systern as well as the gutters from leaves & tree branches. To ensure good quality water the roof should be sealed with a marine sealant. This will eliminate the porous roof tiles or cement from accumulating bacteria.
Google "rainwater collection". There are a few good websites out there with good advise & tips about this project.
Georgios