RO/DI Unit Configuration

[evoracer]

I have read differing statements from every site on how to properly set up a RO/DI unit.

The one that makes the most sense is:
10 µm (micron) sediment filter (filter out anything over 10µm)
5 µm carbon block (remove between 9.99 and 5 µm)
1µm carbon block (remove between 4.99 and 1 µm)

This configuration allows each filter to prevent the next from premature plugging, and brings the final product down to 1 µm, which is smaller than what I have seen the recommended maximum for a RO membrane (generally 5 µm).

Then into the RO membrane, then I would tee off to drinking water supply and into the DI resin. Is there any benefit to two DI's? If the first is capable of bringing TDS down to zero then I would say no, as long as you stay on top of maintenance, right?

Also, we have had some incidences around here lately of chloramine poisoning in some local tanks, due to drastically raised levels in the local water supplies after hard rains. The advanced levels are quickly exhausting carbon blocks and making it through into the final product. Unfortunately, this was not realized until damage had been done to a few local tanks, as most don't test for chlorine in their freshly made RO/DI. There are chlorine filters available, called catalyzed carbon filters. Anyone use these? Would you just replace the standard carbon blocks with one of these when needed?

 

[jmann]

I have a 5 stage, 5mic sed, 1mic sed, .05mic carbon block, ro mem., di cartridge. Here is one from Bulk Reef, you might want to also check Buckeyefieldsupply.com, that is where I get mine but I didn't see one for chloramine.
http://www.bulkreefsupply.com/store/chlorplus-10-carbon-block-chloramine-removal.html

 

[dbdisok]

I just went though the process of researching and ordering a RO/DI unit fro the Filter Guys. They are a RC sponsor. I liked that when I called I got a live person who keeps reef aquariums and is dedicated to improving water quality for this hobby.

The RO/DI unit I ordered is set with filters to remove chloramines.

I would recommend you call several on the RC sponsors and see who you feel the most comfortable with ordering from.

My RO/DI shipped the day after I placed my order and should be here next week.

 

[Randy Holmes-Farley]

The advanced levels are quickly exhausting carbon blocks and making it through into the final product.

Exhausting them? Or penetrating through them at day 1?

There are many things that might get through an RO/DI if the TDS is not kept to 0 ppm. Was it 0 ppm TDS on those systems with the claimed chloramine damage?

Did you ever actually measure chloramine in the effluent?

 

[Randy Holmes-Farley]

Is there any benefit to two DI's? If the first is capable of bringing TDS down to zero then I would say no, as long as you stay on top of maintenance, right

I prefer 2, but not because the water is necessarily any better. Two DI's allow a method of use which the first can become more effectively used rather than having to discard it at 1-2 ppm TDS. You can run the first one until its effluent TDS reaches half of the TDS of the water coming into it, then replace it.

These have more on chloramine and RO/DI systems removing it:

Chloramine and the Reef Aquarium
http://reefkeeping.com/issues/2003-11/rhf/feature/index.htm

Reverse Osmosis/Deionization Systems to Purify Tap Water for Reef Aquaria
http://reefkeeping.com/issues/2005-05/rhf/index.htm

 

[dbdisok]

Randy,

I read the Chlorimine article you authored. I went to the Hach site and looked up the test kit you recommended. I was wondering if the test kit you listed is for chloramine as well as chlorine?

Also, I could use a little help in understanding the difference between "Free &Total" when talking about chlorine.

Thank you.

Dale

 

[johnd651]

just my 2 cents,

i would go with a 5micron sediment filter, then 5 micron catalyzed carbon, then 1 micron carbon

that will get rid of choloramines

 

[Cdaubs]

Hello. :wave:
I'm new on here and have a question regarding my RO/DI unit. I have a 3 stage unit and recently replaced all three filters. Water pressure was running at about 40psi. I then replaced my membrane with a 50GPD and matched flow restrictor. Now my water pressure won't go above 20psi.
Is something wrong?
Thank you in advance for your help. :thumbsup:
Charlie

 

[johnd651]

where in the system is your pressure gauge?

 

[Randy Holmes-Farley]

"Total chlorine" counts chloramine and "free chlorine" does not. There may be little need to distinguish them when trying to determine whether an RO/DI is removing chloramine, and I'd use the "Total" value. The Hach kit listed is good for both.

 

[chuckreef]

For me, three are two benefits of having two DI columns.
One, I can sleep through the first one becoming exhusted and not worry much because the second cartdridge will catch it and good water will still go into the tank.
Two, when the first one beocmes exhausted, I can swap the second into the first position and install a new second one, allowing, (as Randy said), you to get maximium use out of the first positon DI cartridge.

 

[Cdaubs]

John,

Thanks for taking the time to try to help me out. The meter is "T"ed off the line between the second canister filter and before the RO membrane.

Charlie

 

[johnd651]

interesting...i am not sure.

it might just be that your previous membrane was "clogged" and was causing a build in back pressure. With the new membrane there is better flow, and hence less pressure will build.


if you can check, what is the pressure before the unit? if there is not a major difference (+/- 10psi) i would not worry.

you can also check TDS (total dissolved solids) and if you are getting zero (assuming you are using DI) then the unit is working

 

[rob.mwpropane]

It's a little late in the thread but +1 for the filter guys. I have always gotten a person to answer when I call, and they inform me of more than I ask. They have even gotten me to buy less than I intended because he said there was a better, less expensive way. I am a customer for life.

 

[iamwrasseman]

taggn along

 

[Cdaubs]

John,

Yes my TDS meter shows 000 at the end of the entire system. I will see about checking the meter earlier in the system line.

Again, Thank You! :thumbsup:

Charlie

 

[Buckeye Hydro]

I have read differing statements from every site on how to properly set up a RO/DI unit.

The one that makes the most sense is:
10 µm (micron) sediment filter (filter out anything over 10µm)
5 µm carbon block (remove between 9.99 and 5 µm)
1µm carbon block (remove between 4.99 and 1 µm)

The idea a decreasing pore size is a good one, but it should ba applied only as far as the sediment filters. The pore size on the carbon blocks should be about equal to or larger than the smallest pore size on the sediment filter(s). The will keep your carbon blocks largely free of sediment and available to do their intended job.

Then into the RO membrane, then I would tee off to drinking water supply and into the DI resin.

If you are planning to use a pressurized storage container for the RO water, plumb it so that the tank water doesn't work its way back through the DI resin when you make DI water.

There are chlorine filters available, called catalyzed carbon filters. Anyone use these? Would you just replace the standard carbon blocks with one of these when needed?

The critical issue with chloramines is providing adequate contact time with the carbon. The CGAC helps here in that it is an especially fast acting carbon. In most situations one carbon block should be sufficient, but as you've seen, a second carbon stage is some pretty cheap insurance to make sure the chloramine is addressed. A second carbon block would probably be fine rather than CGAC followed by a carbon block.

Russ