Permeate tank

[adk1]

Must it be stainless steel and what is the rule of thumb for its capacity compared to your ro?

[tuckermtn]

stainless not required. I went for 3 years with a 1100g vertical poly tank for a 600RO before now using a old 800g milk tank.

love the milk tank because it drains fully

[Moser's Maple]

Must it be stainless steel and what is the rule of thumb for its capacity compared to your ro?
Minimum of 1 gallon of permeate storage per 1 gallon of your ro rating.
Eg.... If you have a 600 ro then you want a minimum of 600 gallons of permeate storage.

[wiam]

Minimum of 1 gallon of permeate storage per 1 gallon of your ro rating.
Eg.... If you have a 600 ro then you want a minimum of 600 gallons of permeate storage.
That is the rule of thumb. I believe more is better. For extra washes/rinses or short run days you still have enough to wash/rinse.

[ennismaple]

We have 2x800 gallon tanks for our 2 membrane RO. Allows us to do a short rinse or two through the day and the rinse after high temp shutoff is a long one.

As long as your tank completely drains it doesn't have to be stainless.