RO/DI - Podcast Episode 105

[Rob]

In this show i cover the ins and outs of Reverse Osmosis and Deionization. discussing wht it is, and how it works.
i think work through various common questions that come up regarding water filtration and the use of RO / DI

Here is a run down of the show topics
- Reverse Osmosis
- Prefilters
- - Sediment Filters
- - Micron Filters
- - GAC (Granular Activated Carbon) Filters
- Deionization

- Should i use more than one DI Filter
- Testing and monitoring water quality
- What is TDS and how a TDS meter works
- Zero Waster RO / DI units
- Supplementing DO / DI water
- RO / DI system maintenance
- RO / DI water storage and leaching concerns



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[rroselavy]

Fantastic show Rob!

I installed my RODI about 8 months ago, but I didn't really understand exactly how it works until this podcast. You have proven to be an expert at explaining technical information while at the same time being very conscientious about your target audience. Just enough geekery amongst the more topical info. Good deal.

Looking forward to the video - I believe I own the same RODI unit as yours, so it will be even more valuable to see you replace the media. Mine must be used lightly compared to yours, so it still may be a while before I have to replace my filters.

BTW: The instructions that came with my unit recommended that the user shake the unit every once in a while to help prevent settling (or channeling?) of the media. Do you do this with yours, and how often?

-S

[Rob]

hey, thanks.. i was worried i went a bit too far into the technical details, im glad to hear you thought i held good ground...

as for shaking, i honestly dont, however, i can see how that would be a really good thing to do..
i will try and mention it on the video show i do.

[Phurst]

I do shake mine from time to time as sometimes it looks like my DI resin is settled a little too well.

[NaClFinatic]

I noticed the channelling in my DI and shaking helps but I rigged my DI canister to be vertical instead of horizontal and I don't think it really needs to be shaken like that now.

Mostly it seems that the used beads tend to float more than the ones with capacity left. In horizontal position this creates layers and the water tends to flow easier through the upper used layer. When in vertical orientation and the water has to go through (mine flows bottom to top) it is forced to pass through the unused bead layer.

IMO vertical works much better. (Anyway I hope that is what you are talking about, I haven't gottne to listen to it yet!)

[doctorthompson]

Great show, Rob. Haven't had a nice ultra-geeky episode for a while.

For anyone looking into DIY Kati-Ani and concerned about the cost of resin replacement without having the RO prefilter stage: I've heard quite a few people (including Anthony Calfo) mention that replacement resin materials can be quite affordable when purchased in bulk quantities from places such as Spectrapure. If you're not afraid of working with dangerously strong acids there are also methods you can use to recharge the resins and extend their life.

Caveat: Since I've never bought or used anything from Spectrapure (yet!) I must warn the readers of this message that Your Mileage May Vary.

[Pinecone_Jeff]

Great show, Rob. I didn't think it went too techy either. It actually helped me understand just what goes on in those mysterious canisters! :P

I do have a question though. Do you, or anyone else here, know of a RO/DI unit that can be used for home use as well? Hook ups for a drinking faucet on the kitchen sink and another line that goes to the ice maker in the freezer? I've seen units that have a reservoir. How would all the plumbing work with all that and a source for top off water/salt mix water for my tank?

I only ask as it would be a major selling point for my wife!

[Danamck]

Rob -

Great show. Don't appologize for the technical stuff! We love it!

Here's something that I do that I believe helps extend the life of my RO and DI filters. I replace the mechanical and carbon filter more often than the other filters. This way I believe that I extend the life of the RO and DI filters, which are by far the more expensive of the four. I also make about 50 gallons of RO/DI water a week, and my local water is very poor. But after a few months, my mechanical filter is a dark rust color.

My replacement schedule is as follows:

Mechanical - 2-3 months
Carbon - 4-6 months
RO - 1 year
DI - 2 years

So far this seems to work. My TDS meter never gets above 10 ppm.

I also am going to look into the DI only rechargable filters. Given the amount of water I make per week, and the fact that my plants can only drink so much water, it makes sense for me. I will give you an update if and when this happens.

[Rob]

Originally Posted by Pinecone_Jeff

I do have a question though. Do you, or anyone else here, know of a RO/DI unit that can be used for home use as well? Hook ups for a drinking faucet on the kitchen sink and another line that goes to the ice maker in the freezer? I've seen units that have a reservoir. How would all the plumbing work with all that and a source for top off water/salt mix water for my tank?

I only ask as it would be a major selling point for my wife!

the unit i use also doubles as drinking water
this is the one i have
http://cgi.ebay.com/AQUA-SAFE-MAXIMU...QQcmdZViewItem

a word of caution, once you start drinking this water you will not be able swallow regular tap water.. its gross... lol

[Russel P]

I can't wait to listen, Rob! I'm buying a LFS and there is no filtration in the store! I even have a small one at home. So now I'm trying to decide between cold sterile and RO/DI. I need some pretty good output as I plan on doing all my water changes the same day and storage tanks cost more than the units, it seems.

[Rob]

i don't think one of these units can handle the the output needed for a LFS. Not being involved in that i am not sure what to recommend for such a purpose.