500l for two peeps doing domestic? I don't think so. What rate of flow is that?
About 1.5 litres per minute.
We have a 500 litre tank in the vehicle that does all of our domestic rounds with two operators. Only occasionally do we use it all up, on Wednesday we came home with about 150 litres still left.
For our commercial work we use between 500 litres and 850 litres per day for two operators. The question was what tanks would you go for if you started again. My answer was based on our exact current usage.