RO/DI decision time

[AZDesertRat]

Kidney,
You still want a good quality RO/DI with all the normal filters. Thewhole house system may remove large sedimernt and particulates but the RO prefilter should take it down to 0.2 to no more than 1 micron. Also RO membranes threshold for chlorine is .01 mg/L and I'm sure your whole house can't do that, it takes a really good carbon block to accomplish that and last any amount of time.

[five.five-six]

Originally posted by Reno Reef
HAHA you sound like me. I had to lug 2 shopping carts around the store to get the 6, 5 gal jugs to the machine for over the last year. And recently I have notice a large HA outbreak in both of my tanks. I asked a guy I know with who works there when the last time they were serviced, and he told me they had cut their contract with the company and were just waiting for them to pick up the units. When I asked how long ago they cut the contract he said it had been over 3 months... so yep my RO water hadnt had a filer change in AT LEAST 3 months.

So I ordered from melevsreef.com should be here tomorrow.

yea, i am 40 freaking years old, standing in the rain, I support a family and won't even buy myself a water filter [smacks head]

[Macimage]

yea, i am 40 freaking years old, standing in the rain, I support a family and won't even buy myself a water filter [smacks head]

That really made me laugh tonight!!!

Joyce

[kidney514]

Originally posted by AZDesertRat
Kidney,
You still want a good quality RO/DI with all the normal filters. Thewhole house system may remove large sedimernt and particulates but the RO prefilter should take it down to 0.2 to no more than 1 micron. Also RO membranes threshold for chlorine is .01 mg/L and I'm sure your whole house can't do that, it takes a really good carbon block to accomplish that and last any amount of time.

OK do you have any perticular model that you recommend?

[AZDesertRat]

There are lots of good choices. Start with the Reef Central Sponsors that deal almost exclusively in RO and RO/DI systems, they know best.
www.buckeyefieldsupply.com
www.spectrapure.com
www.melevsreef.com
www.airwaterice.com
www.purelyh2o.com
www.thefilterguys.biz

Expect to spend between $150 and $230 or so for a good basic unit with everything you should need including a TDS meter and inline pressure gauge. Look for things like a full sized 10" 20 ounce vertical refillabe DI canister and cartridge, a 75 GPD RO membrane and good quality low micron rated pre and carbon filters.

[DOTZ]

Just a FYI.. You should never test your salt water with a TDS meter. The salt in the water can ruin the probes and the meter. Only check fresh water with it.

[Artisan Corals]

I wanted to address some points that AZDesertRat stated a couple days ago:

Kati/Ani DI systems have their place but are not as efficient as a good RO/DI system --- An RO system alone achieves 96-98% efficiency. The DI add-on gets you up to 99%. A Kati Ani or other high end deionizer alone will get you to 99% without the prefilters or membranes.

and also require harardous chemicals to recharge the resin --- This is true, you need a 6 part water to one part muriatic acid dilution and a similar dilution of sodium hydroxide/water.

You will also find you will never ever be able to recharge the resin back to 100% as it requires heat too to accomplish this --- You do not need any heat to regenerate the Kati Ani resins. Many units (resins) have been regenerated over and over for decades - meaning they regenerate to 100% in about an hour with the above mentioned chemicals alone.

DI will not remove non electrically charged contaminates so is not as effective as a membrane --- each purification system has flaws. You could also say RO only takes out particles over a certain size so it is not as effective as Kati Ani. The bottom line is both filtration methods have problems removing some pesticides and do not remove all silicates. Like RO, the Kati Ani does need good activated charcoal to assist in the elimination of chloramines. Otherwise there are no major differences.

I suppose if I hada tpa TDS or 50 or less I would consider it but when the national average TDS exceeds 250 its not an option for most. ---- Kati Ani has been made in Germany since the early 70's and it is very popular in Europe. Their water is much worse than ours on average. In a part of Switzerland, the TDS is 825 and the Kati Ani is effective but in that case they use two Kati units with one Ani unit. Higher TDS or GH will require higher costs (more regenerations), but this would also cause more frequent membrane and prefilter changes in an RO system. The total cost per gallon of purified water is much lower with the Kati Ani.

And no wasted water with a 385GPD throughput.

Bruce

[Fishbulb2]

Originally posted by Artisan Corals

DI will not remove non electrically charged contaminates so is not as effective as a membrane --- each purification system has flaws. You could also say RO only takes out particles over a certain size so it is not as effective as Kati Ani.

Bruce

Hello Bruce,
I think I have to disagree with this statement above. You give the impression that Kati Ani will filter down to a smaller micron size than RO but my understanding is that this is certainly not the case. The prefilters in an RO system will filter down to .35 or 1 um depending on the filter. The Ani-Kati system has no prefilters and essentially will not filter out particles appreciably at all. Is that not correct? I think for particle filtration the RO system will perform much better. I would not expect the Kat-Ani system to perform any better than the DI component of an RO system for filtration in general.

[AZDesertRat]

The simple truth is they won't. They have limited uses.

[Fishbulb2]

I would also like to clarify how an RO membrane works. I think there is often a misconception that they filter based solely on absolute particle size. In reality, they filter and reject particles based on their apparent size in water due to hydration. So small molecules that are heavily charged will be rejected far more easily that large molecules that carry no charge or are weakly charged. Examples of this are how RO membranes will reject Na+ more easily than say NO3- or PO4- even though these molecules are much larger than a single sodium ion. In solution, the sodium ion will will form a large complex with polar water molecules and it is this apparent size the will allow it to be rejected by the membrane. So RO membranes actually reject particles as much based on their charge as their size (because it is in part their charge that dictates their size in water).

A little off topic I know, but this thread started out on understanding how these filters work so I thought I'd though this in.

FB

[five.five-six]

I just want my fish to look good and not stand out in the rain and driving wind in the middle of the night with a bag of quarters and a bunch of jugs while the night crew at the grocery store contemplates calling 911 to report a strange looking vagrant standing outside near the water dispensing machine

[Artisan Corals]

I think we are both correct, just coming from different directions.

I was referring to the removal of minerals and organics that we don't want in an aquarium. If you have a problem with sediment, the Kati Ani is not a filter, but it is a purifier. You can obviously add a sediment filter to a Kati Ani if you want or need to. The point was that the Kati Ani does not require that all sediment is removed to operate at full efficiency. The RO is a filter membrane that would become clogged and not operate fully without the sediment prefilter.

The typical mixed bed canister attached to an RO system does work similarly to a Kati Ani. The difference is that it is not rechargeable and thus expensive to replace. That is why it is placed after the prefilters and RO membrane. The Kati Ani has two separate canisters of resins that can be recharged over and over again at a very low cost.

The Kati Ani purifies water by way of electron attachments and the RO filters based on size. The size of the particles removed the the RO membranes are determined by the compound created by electrically charges. Different approaches to a similar end result - 0 TDS.

These Kati Ani units are very very popular in Europe since they have been manufactured in Germany for 30+ years. Many of our most experienced "founding" aquarists have used Kati Ani on their own systems for years partly because larger scale operations need the lowest cost purification. I can't name names, but I know that three of the 2007 MACNA speakers use them personally and maybe more.

Bruce

[AZDesertRat]

Anthony Calfo uses kati ani and him and I disagree on their usefulness. We agree to disagree. He has been in my home and photographed some of my corals and has seen how well my RO/DI worked but he still uses his DI system. Not for me and I still stand on the fact they do not work as well but do have their place, just not with bad water.

[Artisan Corals]

Fair enough. I guess I'm in the same boat as Anthony - agree to disagree.

[five.five-six]

so I just spoke with my water department and they said they do use cloramine... how bad is that?

[AZDesertRat]

Chloramines mean you need a very good carbon block like a 0.5 micron Matrix Chlorine Guzzler or catalytic carbon folowed by a good carbon block and a high quality DI. By high quality I mean a vertical 20 oz 10" canister type with a nuclear or semiconductor grade mixed bed resin. The carbon removes the chlorine portion and the DI removes the ammonia that gets by the RO membrane.

[Fishbulb2]

I'm not surprised you have chloramines in your water since I am also in SoCal and they use it here. Definitely use the highest quality carbon blocks that you can. What I do to help prevent any chlorine break through is to increase the contact time between the water and the carbon block. I do this by having a second carbon block. So my prefilters run sediment, carbon 1, then carbon 2. To prevent from having to replace twice as many carbon filters , I rotate and replace the carbon blocks every 6 months. What I do is throw carbon block 1 away in the trash and move carbon block 2 up into the first position. I then add a second carbon block behind it. This way I always have a fresh carbon block in position 2 and the block in position 1 is still relatively fresh (since it was previously shielded). I measure the chlorine in my waste line periodically and have not had a break through yet. It's also amazing the difference in discoloration between the first and second carbon blocks. I think the back up block is a good idea and safety measure for those with chloramines in their tap water.

FB

[five.five-six]

ok I am ordering a "Catalytic Carbon stage to split the chloramine to products more readily removed by the remaining stages in the system"

but my question is, how bad is this stuff?

would it have anything to do with a few mystery "Poof that frag went white" episodes I have had?

['06Siguy]

Great info in here. I'm really glad I found it. I just hooked up a RODI I got with my tank. It seems to be working good. A couple wuestions though... When not in use, the DI chamber is full of water, but as I open the product valve, it empties on the outside of the cylinder.

Also, is this a good membrane? You said there was higher TDS with larger membranes, so how does this rate?
http://theh2oguru.zoovy.com/product/TW301812-150

Thanks.

[Fishbulb2]

Originally posted by five.five-six
ok I am ordering a "Catalytic Carbon stage to split the chloramine to products more readily removed by the remaining stages in the system"

but my question is, how bad is this stuff?

would it have anything to do with a few mystery "Poof that frag went white" episodes I have had?

I would REALLY go with two standard .5 um chlorine guzzler type carbon blocks instead of the refillable loose activated carbon variety. The carbon blocks will be a lot easier to use, probably have less carbon dust, and will certainly provide you with enough protection (especially if you double up on them as I described). Jim from filterguys suggested this to me and I'm glad I went this route without dealing with the activated catalytic carbon.

If the water you were using before had chloramines still in it when you added it to the tank, then yes, it could explain a lot of death. Chloramines are also worse than chlorine gas because it will not off gas by leaving your water out or aerating the water.

[Fishbulb2]

Originally posted by '06Siguy
Great info in here. I'm really glad I found it. I just hooked up a RODI I got with my tank. It seems to be working good. A couple wuestions though... When not in use, the DI chamber is full of water, but as I open the product valve, it empties on the outside of the cylinder.

Also, is this a good membrane? You said there was higher TDS with larger membranes, so how does this rate?
http://theh2oguru.zoovy.com/product/TW301812-150

Thanks.

The fact that your DI chamber empties on the outside when you draw DI water is no problem at all. The water is still forced through the resin via then internal chamber of the cannister. This is common and not something to worry about.

That membrane is also sold at buckeyefield supply and appears to be becoming more popular. It's generally advertised as a 98% rejection rate but virtually no one has ever reported their actual rates here on RC. Thus I don't really know. If you can get by with a 75GPD filmtec membrane, it is probably a more "sure" thing. At least you can get dozens of users input here on RC. I may try that same membrane sometime in the future if I start seeing positive reviews about it but until then I'll stick with my spectra select membrane. At least, I would contact the vendor and tell them you are interested in the membrane. Ask them the rejection rate and what minimum rejection rate would you need to return the membrane as defective. If they say anything less than 96%, I think I would just stick with the proven Dow membrane.

FB

also there is someone here that is running two of these membranes so he may be able to tell you what rejection rate he gets on each of them

[AZDesertRat]

When you can get a good 150 GPD membrane they are great. I have one from Spectrapure that they were able to get to pass their rigourous testing to become a Select Series 98+% rejection rate membrane. Unfortunately they quit carrying them as they were not able to get a large enough supply of them to pass their testing procedures. Mine was one of the first and it has been 99.23 to 99.35% rejection ever since May 07. I do believe just like other membranes though this is a rare exception, 96-98 is probably the best you can expect and probably closer to the 96%.

[beanoil]

Forgive me for stepping in on a great thread, but I think this may help the OP as well. Fishbulb and AZDesertRat, you've confused me on the permeate pump. I too am using a pressurized storage tank hooked up to an icemaker. I bought an RO/DI unit from one of the RC sponsors mentioned above (1 sediment, 2 carbon, 100gpd membrane, 10" vertical DI canister), and I'm getting 8 gallons of waste to 1 gallon of good. I've been thinking that it has something to do with the pressure tank. Is a permeate pump the fix, and if not, any idea what is? Again, thanks for the great info here.

['06Siguy]

Well I did buy that membrane and am useing it now. When I received my reefkeeper unit, it didn't have a membrane, so I figured since it says 98%, I'd be fine. I don't have any test equiptment though. How much are those handheld unit you were talking about?

Also, I know TDS stands for total dissolved soilids or something, but I was wondering how important it is to have it at 0. Let's say my membrane is only getting 96 like someone had said earlier...does that just mean I'll go through the resin sooner? What if I did a by-pass on DI and put the 96% water into my DT. What would be the outcome? I think I'm starting to understand this stuff. It's a lot to take in though. But thanks again for the great info!

['06Siguy]

Oh, nevermind about the testing units, I found some at airwaterice.com they're not as expensive as I thought they'd be.

Thanks again for the help.