The 5lt Passive Hydro Pot is very useful, decorative and easy to use. It was hand made from a discarded water softener container and a mini yogurt bottle that would have added to the waste management problem but rescued in the nick of time. You will most likely have more of these pots hanging around than any other. The water level is discernible at a glance. The entire container holds 5 litters, 2 in water and 3 in substrate. Their are afew variations to this model. The price is easy so I am sure you will find one that is suitable to your taste.