From The Archives: Friday Morning Quick Tip #30: The Horizontal Position Isn’t Advised

by Mark Callahan · 28 comments

in Reef Enthusiast,Reef Junkie,Tank Dabbler

I’m a big fan of  using Reverse Osmosis DeIonized (RODI) water for your saltwater tank.  And if your RODI unit has a certain stage in the horizontal direction, it needs fixing

Tagged as: DeIonized water, di bed, RODI unit, RODI water

{ 28 comments… read them below or add one }

Michael February 1, 2013 at 8:14 am

What would be the best method to test the water quality between the two setups? I have a horizontal DI bed, much like the one you displayed, and the water always appears to fill up the entire medium. I can see that if you don’t have the proper amount of water pressure, or medium in the DI that it may not be utilized properly.

Brian February 1, 2013 at 8:57 am

So does that mean the Coralife RO/DI is a bad design, their entire line is built with the DI horizontal?

Binnemann February 1, 2013 at 8:58 am

‘m Also a big fan of the reverse osmosis system.
Without which it will not be easy.
mfg Bernd

Josh February 1, 2013 at 8:59 am

I have a TDS meter to test mine, it has a probe after the RO module and one after the DI.

RICH February 1, 2013 at 8:59 am

HI MARK
WOW! JUST HOW MANY FISH AND REEFERS REALIZE THIS VERY INFORMATIVE TIP THANKS MARK

Mark Callahan February 1, 2013 at 9:01 am

Michael…the issue with the horizontal bed isn’t so much about quality of water as both a vertical and horizontal bed can yield 0 TDS water. However, a horizontal bed won’t last as long as the water passing through it can come in contact with less media, causing the media that is in contact with the water to exhaust quicker. The result will be parts of the media that aren’t exhausted, yet the water coming out of the DI bed won’t be 0 TDS

Chris February 1, 2013 at 9:13 am

Mark,
Do you have a list of companies that make rodi units that do not have a horizontal bed?

Chuck February 1, 2013 at 9:15 am

Great tip mark. Never even crossed my mind that the ‘filter experts’ who I bought my RO/DI setup from would sell a horizontal DI design that helps sell more DI media… go figure. I’m thinking rather than completely replacing the horizontal-style design (I’ve got the same you showed in your video) it could easily be re-plumbed to sit vertically… would only take a few fittings and tubing, and a clever way to hang/mount it. Thanks for all the great tips over the years — Keep up the good work! This one will definitely be put to good use on my system asap.

Postaldave February 1, 2013 at 9:49 am

Can you just rotate up the one you have or do you need to purchase a vertical designed one?

Tina February 1, 2013 at 11:16 am

If I have a 5 stage system with a horizontal bed, how would I retrofit it with a vertical bed? I do notice it goes through resin (especially if I don’t pack it thoroughly).

Dave February 1, 2013 at 11:17 am

Hey Mark,
I have a TDS meter and since I installed a booster pump I am getting more life out of my DI resin not to mention all the other filters. My question is what is an acceptable TDS level before I change my filters? Presently I have a reading of 2.

Mark Callahan February 1, 2013 at 11:52 am

Dave..if your TDS is above zero, then I’d start by changing the DI resin. Then move onto the other filters.

Mark Callahan February 1, 2013 at 11:53 am

Postaldave & Tina…I’ve had mixed success rotating the horizontal beds vertically. Even with the pads at the ends of the filter, the media still escapes and the DI resin doesn’t last as long. I recommend replacing the horizontal DI bed with one designed to be vertical.

Adam Blanden February 1, 2013 at 12:42 pm

Great tip! The issue with the DI column is essentially in the media packing. One of the primary things my laboratory does is protein expression and purification — so I’ve run hundreds of chromatography columns. Even when you pack a column vertically, you have to be careful about making sure the bed settles evenly and that you don’t force little “paths of least resistance” through it that the solution can flow through (a phenomenon called channeling) — the difference in efficiency is pretty striking, and that’s just with little channels, that alone with the column horizontal! Kinda makes you wonder who thought that was a good idea…

Bob February 1, 2013 at 1:33 pm

I have SpectraPure FR-25, 25 gallons per day. It has 3 vertical filter chambers one 1 horizontal chamber on top, SpectraPure® Maxpure 25 GPD RO/DI System, is this a vertical or horizontal unit? Thanks, Bob

dave from brooklyn February 1, 2013 at 4:46 pm

My tds still reads 0. My parameters are good. My water here in NY is pretty good. Would you st change the redin after a year?

Joe February 1, 2013 at 5:15 pm

So are you saying if we have a model with a horizontal bed that can not be made vertical we would be better looking at a new system? Mine is a compact system from a known company that cannot be changed.

System would still work but in the long run would cost you more money replacing filter more frequently.

Big Mike February 1, 2013 at 5:16 pm

Hi Mark. Thank you for all your tips and advice. They have been a great help the last year which is my first year in the hobby. Here is the situation. I have a 75gpd BRS 5 stage RO/DI system that I bought a little over a year ago. My TDS reading as of today is 3 ppm. The unit came with the color-changing DI resin and the center 3 inches hasn’t really changed color yet, at least not like the top and bottom. I am just wondering if you change the resin out as soon as it is not 0 ppm any more or do you have a certain number you will wait to reach? In one of Vivid Aquariums videos Dave says he waits until 10 ppm before he will change DI resin and filters. I do not have nuisance algae growing any where and the tank’s parameters have been excellent. Thanks again for all the videos you have produced. You have made this hobby really enjoyable. My first couple months were rough. I made a ton of rookie mistakes. LOL!

Rick Schmidt February 1, 2013 at 5:37 pm

Mark:

My RO/DI unit has a horizontal DI bed; but with a few pieces of tubing and one extra connector I can McGyver it into a vertical position. My question is whether my inlet to this stage should be on the bottom or the top of the cartridge.

Sean February 1, 2013 at 8:11 pm

Do you run stereilizers on your tanks. Have you done a clip on them?

Mark Callahan February 2, 2013 at 5:53 am

Sean…I don’t recommend sterilizers.

Mark Callahan February 2, 2013 at 5:54 am

Rick…inlet should be at the bottom.

Mark Callahan February 2, 2013 at 5:55 am

Big Mike…I change out my resin whenever the TDS of the water coming out of it is anything more than zero. The cost of DI resin is much cheaper than dealing with an algae issue that might get caused by using your DI media until the TDS reaches a higher number.

Mark Callahan February 2, 2013 at 5:56 am

Joe…you can easily add on a DI vertical stage for not a lot of money. Once the DI resin in the horizontal stage runs out, you can just leave that stage empty.

Mark Callahan February 2, 2013 at 5:58 am

Dave…I change my DI bed whenever the TDS of the water coming out of it reads over zero. If that takes 2 years, then great! If it takes 3 months, out the resin goes. Every year I change out the rest of the DI filters (not the RO membrane) though regardless of the TDS reading. It’s much cheaper to change out 3 filters than to deal with any headaches that could be caused by bad RO filters.

Mark Callahan February 2, 2013 at 5:59 am

Bob…the vertical chambers are likely the sediment and carbon block chambers, not the DI chamber. The DI chamber will be filled with a media that is probably brown or blue and this media will probably change colors as it gets used up

Mark Callahan February 2, 2013 at 6:00 am

Adam…great point and a great time to remind people of this quick tip I made on the same subject.

Steve Dodd February 3, 2013 at 7:36 pm

Hi Mark , how can I email you to ask a few questions , Im not on twitter , (or twatter as we call it here in the U K) , or facebook and have no desire to be , but i cant find a contact for you outside these two.
could you let me know
Steve Dodd

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