bought big van an brodex a few months ago the tank is 650 litre which is not tiny by any means BUT the tank lasts about 8 hours but that is on pump presure one which i find really slow to use ,i like to use at least a 2 or 3 ,which means me comin home after only 4 hours ,also if i get a lad to help me an we both work on presure one then we would both be home after 4 hours so whats the point ,,cant upgrade to 1000 litrs yet ,surely all you other top jolly window cleaners have the same problem ..i mean even an eco trolly will only give me another 45 mins ...maybe im a bit naive and there is an obvious solution but hey thats wot sites like this are for cheers gang