Hi Mate,
I have used varitech and they are a good company. How much water will you use a day? How many hours do you work?
I still use a merlin ro as it suits my needs i do 3 to 4 hours window cleaning a day and have an ibc 1000ltr tank in the garage which i keep full. Aprox 350 ltr will last 4 hours.
Cheers Jay