The RO-86 is a larger storage tank that holds up to 50 gallons at different pressures. It comes pressurized at 5 PSIG. This is the size of storage tank you would need to meet the kind of requirements you described:
- 300 people / day use the system
- 20 gallons per day; possibly up to 40 gallons on a Sunday
The RO-86 tank can be seen in this document:
http://www.amtrol.com/pdf/reverseosmosis.pdf
Thank you,
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