RODI question

[moortim]

I have been getting a RODI setup going after buying water for several years and keep running into questions. I want to start up this thread so as I come up with questions I can just ask them here.

First question:
How long do you flush a RO membrane to clean it out?

By the way I wanted to put in a plug for The Filter Guys, I sent them a big list of questions and they were very quick to respond and when I sent them an order they refunded me $5 for a shipping overcharge. Very few people do that when ordering online. Thanks guys.

 

[tdgates10]

I flushed mine for 2 hours before my first use and then every month or two I do an hour flush.

 

[Scooterman]

I flush mine a few seconds before & after each time I use it but really the Filterguys said once a month for a minute or so is plenty, any more is wasting water. Now If you use an ATO connected to it, you have to deal with creep but that is another story.

 

[moortim]

Is there anything I should do to my unit to store it? I only filter water once a week so it sits under the sink most of the time.

 

[returnofsid]

Sitting is just fine as long as the membrane stays wet. I'd suggest running water for a minute or so before collecting water each use. Other than that, you should be just fine. I've never had any trouble doing as I described.

 

[moortim]

New Question:
What is the advantage of having more than one DI cartridge?

 

[logiktest]

Using the DI gets most of the dissolved solids out of the source water that RO alone can not. Using more than one chamber or cartridge helps to ensure that the resin does not become totaly exausted. If you have two cartidges, the first will exaust faster than the second, so its kind of like having a back up.

 

[moortim]

If you have two cartidges, the first will exaust faster than the second, so its kind of like having a back up.

So it doesn't give you cleaner water, just gives a backup as you mentioned here. Right?

 

[DonW]

So it doesn't give you cleaner water, just gives a backup as you mentioned here. Right?

Yes it does give you cleaner water if the first is not capable of removing the crud the membrane left behind. If you have a high flow system or high incomming tds the second di chamber will help.

Don

 

[moortim]

Yes it does give you cleaner water if the first is not capable of removing the crud the membrane left behind. If you have a high flow system or high incomming tds the second di chamber will help.

Don

What do you use as a way to know if the first di cartridge is capable of cleaning out all the junk? Just a TDS meter? With one di cartridge I get 0 output TDS. Is having more than one di cartridge something I should worry about?

 

[DonW]

Yes you would just check the tds. I like the second cartrige. It gives me plenty of time to be lazy or put off ordering more resin.

Don

 

[moortim]

Another question, how fast does the di resin go bad? I know it probably depends on how much it is having to remove from the water but does it slowly wear out? Or is it good one day and bad the next?

 

[DonW]

Another question, how fast does the di resin go bad? I know it probably depends on how much it is having to remove from the water but does it slowly wear out? Or is it good one day and bad the next?

As long as my incomming tds stays close to normal at 30 I could go 10 months on two cartriges with 7gpd evap and 100g per week water changes. Thats with at least two membranes running a little longer with 4.

Don