At first sight, transparent water containers could be perceived as good options, because it can help the user to see the inner surface walls. The idea is: "when the walls look dirt, it is time to clean them".
However, the big drawback of a transparent container is the rapid growth of algae caused by the passage of sunlight. Instead of using transparent containers, it is recommended to use opaque containers and set up a schedule for cleaning. The safe water storage containers should be cleaned in a regular basis (it is highly recommended before every use) and the treated water consumed in 1-2 days of treating it.
In some publications, it is stated that the maximum interval for cleaning the water containers is one week.
Check the following resource for more details on how to handle the water container.
This question was raised during the webinar "A water professional’s guide to safe storage". If you missed this webinar, please find it here.