RODI

[Zack]

Usually, per week I use about 7 gallons of RO a week for waterchanges and top off, however most commercial units make 50-75 gallons of RO a day, with that being said, what's the smallest available RODI unit that would meet my needs? Or what's the best alternative for such a small need?

[Big_Pun]

just make what you need just means your filter will last longer cause you won't need as much as I do with larger tank.

[Zack]

So filter changes are based on gallons run through them or time?

[polarbear]

Gallons ran through them.

[rrasco]

There are several factors that can affect the life of the filters. It also depends on what filter you are talking about. The membrane lasts quite a while. The carbon and sediment filters will also last a while on their own. They have different ratings depending on the cartridges you have. The DI will exhaust the quickest depending on how clean the water you are supplying to it is. Flushing the membrane regularly and running the filter for longer durations will help extend the life of the DI resin. It's nice to have a dual TDS meter so you can see the readings on what's coming out of your RO and what's coming out of your DI. You'll be surprised how high the TDS gets just sitting between the RO and DI stages (i.e., TDS creep).

[Big_Pun]

I've spent a lot of time on my filter to get the most out of it. purging TDS creep on start up can save you money in DI, basically you isolate the DI cartridge and purge the water from membrane till TDS drops down then you open a valve and let it go through the DI resin.