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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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

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.

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

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!)

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 (http://www.spectrapure.com/St_replac_p5.htm). 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. :)

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! ;)

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.

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-MAXIMUS-II-REVERSE-OSMOSIS-WATER-FILTER_W0QQitemZ150169153278QQihZ005QQcategoryZ206 84QQcmdZViewItem

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

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.

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.

My LFS has a huge super duper system. He would probably be happy to talk to you if it would help.

hi i have a 6 stage RO and after hearing the importance of a DI unit will surely add one, Im from Malta (EU) and my tds reading is about 800ppm!! so was thinking of doing a triple di unit. I have seen calibration solutions for tds meter what is this? and also heavy metal removers (was told to remove lead) do i need one coz of the high tds i have?

Thanks great site and podcast!!

Tom.

Hi Tom and :welcome: to TR.

My sister was in Malta this summer. :) Is the 800 TDS before or after the filter? A calibration standard has a known value. You can use it to see if your meter is working properly. Some meters also have a calibration mode but I think these are only laboratory grade instruments. TDS can come from many elements in the water not just lead. Did they suggest where the lead would come from? Would you still have plumbing in Malta with lead solder? This is still found in older homes in the USA.

I hope she had a good time here, summer is almost over now. I was collecting live rock for my 10ft tank from our sea (would like to hear comments about rock from the meditteranean, they are full of corraline algae and very porous) and now the weather is not letting me continue.

The 800 reading is before the filter, the lowest it got after the filter was about 25, so its not too bad. However my meter's after reading always starts from a high reading about 800 then after about 4min it gradualy starts to come down. Is this normal? and should i wait for the reading to come down before using the water? do i need calibration? thay did not say from where it could come and im not sure what the plubming is made of but i dont think its old.

the unit i use also doubles as drinking water :)
this is the one i have
AQUA-SAFE MAXIMUS II REVERSE OSMOSIS WATER FILTER - (eBay item 150169153278 end time Oct-11-07 19:00:00 PDT) (http://cgi.ebay.com/AQUA-SAFE-MAXIMUS-II-REVERSE-OSMOSIS-WATER-FILTER_W0QQitemZ150169153278QQihZ005QQcategoryZ206 84QQcmdZViewItem)

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


If I am not mistaken, the output of the RO unit has a T connector so one connector goes to a 3-5g pressurized tank (for drinking water) and the other connector goes into your DI stages for the Aquarium water. The pressurized tank can sit under your sink and be connected to one of those thin filtered water faucets.

I bought the Aqua-Safe "Aquarium" model without the tank, and am happy with it despite the less than straight-forward install instructions - but I am thinking of re-installing the unit under my sink and buying the tank and hardware...

-S

Tom,
If the TDS of the water coming into your house drops off after a few minutes I would probably let it do that. It seems like the RO system wouldn't have to work to remove the initial blast of TDS and the filters would last longer. If you don't want to waste water start the filter right after you bathe so the lines in the house have been flushed. I would try add a DI to get the TDS down. Does your public water company issue reports of what is in the water like this http://www.raleighnc.gov/portal/server.pt/gateway/PTARGS_0_2_102999_0_0_18/Consumer_Confidence_Report-2006.pdf Since lead is so hazardous to people I would be surprised it was in the public water supply.

but if the high tds reading is still after the filter it is still going through it than the filters are still working. i hope that its not siphoning back from the drain!

Wow am i glad i listened to this show. I wasn't using DI for a long time and i think it has been one of the contributing causes to my hair algae issue. I just added the DI resin and did a huge water change (like 50%, i was remaking the sump and had to replace a lot of lost water). Now the hair algae is starting to yellow, and, if it is similar to land plants, it means it is dying. Very cool.

I didn't realize the DI part was so critical to the whole thing. Thanks rob !!!

Also, where is the carbon in the filter you have rob? I thought there was some in there but i don't remember where it is. Is it in one of those three big filters under the unit?

My LFS has a huge super duper system. He would probably be happy to talk to you if it would help.

I would be VERY interested in that! Please ask them if they'd mind me calling about that. Thanks a ton.

Just an FYI, I have a big RO system at work (makes about 300 gallons/day) and it was $10,000! This unit is doesn't even have a DI unit, because it is not needed for what i do. Not trying to discourage, just trying to help you prepare for the possible shock you might have. :D

1st off.. Hats off to ROB! I'm sure you spent hours of research to make us fully understand exactly how our systems work. (ill be starting my DIY RO/DI because of robs info he has provided :D j.p)

Ive had this posted on other forums with no success getting answered in the past and ever since i discovered Talkingreef. i have answers to everything. seems like surrounded by bunch of gurus in this hobby which is great!

anyways heres my question (look at pic to understand)

I have my RO/DI system set up in my garage as you can see. my waste line is placed outside to just waste away. The system came with this Steel needed valve (for waste line) designed to puncture the waste plumbing under kitchen sink. so than your waste line from your ro di will join the waste pipes from your kitchen sink.

Is there a reason why I cant puncture pipe for the house water line so my waste water wont go to waste?!?.. only reason i could think of why I should not is.. well its not the purest water for one.. but on the technical side is it because it will have too much pressure to where it will push the water back in the waste line creating a jam?!?!/

http://i233.photobucket.com/albums/ee288/belatube/rodi-1.jpg

Yes, the pressure in the pipes will not allow this to work. Look at it this way. Say you have 45 PSI in your pipes. You would also have 45 PSi feeding into your RO/DI system. You have water coming out of 2 tubes. Your clean water might be coming out at 5-7 PSI, which menas the pressure on your waste line is only 40-38 PSI, which is not enough pressure to inject water into a pipe pressurized to 45 PSI.

Yea i agree with Pearson here. I dig your concern about the "waste" water however, i am living in an arid climate as well.

Having the line outside might not be a bad idea though. Is your line long enough to extend to a flower bed or garden? Or, maybe you can leave it on the lawn, i am sure the grass will thank you :)

yes they are right.. the pressure in the waste water line will b too low causing water to flow in the inlet, and also in where the waste water line is.. this will cause a jam and the RO / DI will stop functioning

Just another question about the ro. When the good water outlet is closed (or tap) the system will be under pressure from the mains. what prevents the water from continuing to go out from the waste pipe? since there is no tap there.

There is an shut off that is incorporated into the unit. When you stop using the output and the pressure in the system builds, the shut off engages and stops the incoming water.

i was worried that the water could keep going in the waste if i was doing something wrong. So if i close the ro tap on the sink and open the flush valve and leave it open it would waste water right?

It shouldnt waste water if the tap is closed, but the flush valve is open. With the tap closed, the system is pressurized and the auto shut off will have stopped the incoming water. You will need to open the tap so that the shutoff disengages. Once that happens the flush valve can be used to flush the membrane.

thanks for the help. So if the tap is closed im sure that no water is wasted?

You would have to check the waste line to make sure that the shutoff is working. If no water is coming out of the tap or the waste line, the unit is not processing or wasting water.

I never liked having the waste plumbed into the drain pipe under the sink for the simple fact that you cant see it work. I have my unit in the basement above my utility sink with the waste line run into the sink bowl. I can see at a glance if the unit is processing water. If I happened to know that the tap was off, but I could see waste water, I would know the shutoff has failed.

I will check if the waste water is ok than. Thanks a lot for all the help. This is the greatest site i have been using so far.

I'm glad we are able to help and that you are here!

just so everyone knows the video show has been recorded.. im going through editing now and it should be out this week.. :)