Hi Lenin, the high color and ...

Hi Lenin, the high color and turbidity in your rainwater might be due to organic matter (leaves from trees?) collecting in the tank and decomposing when left to sit there for a pro -longed period of time without the air (anaerobic decomposition). If you can combat this and prevent the organics getting into the tank - that would be the easiest and cheapest solution. How you do it - depends on the set out of your collection system. If these preventative measures do not fully eliminate the odour issue - then activated carbon filter might help prior to supply to the toilets.  The chlorine will not work well is high level of organics is present.  Regards, Iouri