can someone explain what RO and DI actually means?

[craqerjaq]

I know what it means by definition...but what is the difference between RO water and DI water? Or is the water both at once or does it have to be both? How is it different? I'm not sure if this falls under chemistry...but it's not something that makes sense to me.

I can't say I've ever gone anywhere and seen a store selling something labeled reverse osmosis water....distilled water yes, but not the other.

[Ninong]

In the front of Wal-Mart Supercenters, there will be a tall, blue Culligan "drinking water" dispensing machine. It looks like one of those ATM machines except that it is light blue and it has the name "Culligan" across the top. It also looks like one of the soft-drink dispensing machines you see in fast food joints in that there is a large space to place a one-gallon, or larger, container to be filled up with their delicious "drinking water."

If you bring your own containers, the price is only 25 cents per gallon. You can also buy their 3-gallon containers with little spigots in the front of them at the bottom (several bucks) or simply buy their bottled Culligan "drinking water" that will be on a stand immediately next to the Culligan "drinking water" machine. The bottled gallon jugs are 58 cents each. Or you can bring empty milk jugs from home. To clean an empty container, rinse it very well with plain tapwater. Then fill it with tapwater than has one-half teaspoon of household bleach per gallon of tapwater. Swish water around and let stand three minutes. Pour out and rinse container very well with plain tapwater. Air dry. Seal container.

From the Culligan leaflet:

The Culligan 4-Stage Filtration Process: Tapwater from local municipal water system.

1. Sediment Filters: Reduces particles, such as dirt, rust, algae and oxidized iron.
2. Activated Carbon Filters: Reduces chlorine taste and odors. Also reduces earthy, moldy, fishy tastes and odors.
3. Reverse Osmosis: Reduces dissolved solids and microscopic impurities by forcing water through an ultra fine membrance.
4. Ultraviolet Light: Reduces microbiological contaminants.

Quality Assurance: We use an effective treatment against the broadest range of water impurities and contaminants through reverse osmosis and activated carbon filtration. Our expert water technicians install, register, continually monitor, test and service all equipment. Each unit meets or exceeds stringent local regulations, NAMA standards, and strict Culligan requirements.

For more information about reverse osmosis processing, Culligan - better water. pure and simple. .

The only difference between that and what you would purchase from an online aquarium supply vendor would be that there would be no ultraviolet light at the end and instead there would be a deionizing resin canister. The D.I. canister would be the last canister in the process. The water would go through a sediment filter first, then a carbon filter, then through the R.O. membrane and then through the D.I. filter. The D.I. filter removes most of whatever was still in the water, especially phosphates and silicates.

For human consumption, it is best to leave off the D.I. filtration stage. That's why you will find "drinking water options" available when you look at online vendors selling R.O./D.I. systems for hobby use. Those systems will have a storage tank (usually 3 gallons) for storage of R.O. water to be used as drinking water. That water does not pass through the D.I. cartridge. Those systems will be capable of running with or without the final D.I. stage. You run through the D.I. stage only when you are producing water for your aquarium. It's okay to drink R.O./D.I. water but it's better if you just drink R.O. water. The explanation is way too lengthy for this discussion.

[craqerjaq]

I wish there was a walmart supercenter in my town. Makes no sense...largest town within 60 miles but they put the supercenters 20-30 miles away. Just have a plain old walmart here.

I think I screwed up already because I used tap water along with this to fill up my tank. I don't want to have to start over because I already have the substrate and live rock...but is there still hope if I start using better water when I do water changes?

I'm looking at this thing and wondering if it is any good to make good water for saltwater tanks?? Could I use something like this to avoid having to buy gallon after gallon of distilled water from walmart?

[Ninong]

I think I screwed up already because I used tap water along with this to fill up my tank.

You need to use that or something similar to remove the chlorine or chloramine from tapwater. Actually you can remove chlorine by just letting the water sit exposed to the air for a couple of days. It would take three weeks to get rid of chloramine that way.

So yes, you need to use a product like that (usually sodium thiosulfate is the active ingredient) to remove the chlorine or chloramine from your tapwater.

I don't want to have to start over because I already have the substrate and live rock...but is there still hope if I start using better water when I do water changes?

You don't have to start over. A lot of people use just tapwater after treating with drops, just like you did, especially if their aquarium is not a reef tank. It's just that tapwater can be risky because you never know what's in it and they sometimes put crap in it to "clean out" the pipes without warning you in advance. They sometimes do that in the middle of the night once every couple of years.

I'm looking at this thing and wondering if it is any good to make good water for saltwater tanks??

That is a D.I. filter cartridge. The same thing as the final stage on an R.O./D.I. filter EXCEPT that in an R.O./D.I. filter you have the sediment cartridge, the carbon cartridge and the R.O. membrane FIRST so that the D.I. cartridge doesn't get hit with all of that stuff first.

As the ad copy says, it could be good for 300 gallons or it could be good for only 15 gallons -- -- depending on your local tapwater. When I first set up my tank, I used a much larger version of the same thing (about twice as large) and found that it was only good for about 150 gallons before I had to switch to a new cartridge.

If you check online, there are cheapy portable R.O. filters for less than a hundred bucks. You can even get a 5-stage, 75gpd, R.O./D.I. system for only $139.95. Or, for twice as much, you can get a fancy system with all the bells and whistles. I purchased one of their fancy systems six years ago but it didn't have all those bells and whistles back then. And it was cheaper then.

[craqerjaq]

so with the tap water filter I linked...would I need to do any other steps to make good water? For it's price it's not too bad and I only have a 55 gal tank so I'm not going to need huge volumes of water. I think 75gpd would be a waste when I wouldn't use more than 10 gals a week. So I can get buy with that filter till it runs its use...because I had placed the order yesterday lol...so it's on its way. Just wanted to be sure it wasn't complete junk.

[Ninong]

It will work. The only question is how many gallons you can get through it before it has to have a cartridge change. That will depend on the TDS (total dissolved solids) and other impurities in your tapwater.

You should probably continue to use your drops to treat the water after it passes through the D.I. filter just in case all of the chloramine wasn't removed. Most municipal water districts use chloramine now instead of chlorine. Chloramine is a better disinfectant that chlorine because it lasts two weeks or more whereas chlorine lasts only a day or two.

[craqerjaq]

http://www.ci.stcloud.mn.us/Utilitie...es%2001-09.pdf

the finished water column is what my tap water consists of...I don't speak that language very well...how bad is my tap water compared to others?

[Ninong]

Your TDS is 186. My tapwater's TDS was around 176. It should be zero for a reef tank. With an R.O./D.I. filter, it would be zero. With my first D.I. cartridge thing, the best I could get was around 20 TDS finished product with tapwater going in at around 176 TDS. Some municipal water systems have less than 50 TDS and some have more than 700 TDS.

Your tapwater has high silica at 11 ppm. Could cause diatoms. Nitrate is low at 1.5 ppm. They didn't report copper levels. Hopefully those are extremely low. Unfortunately, the levels that are safe for human consumption are entirely unsafe for a reef aquarium. In most tapwater, copper is not a problem. It can be toxic to some invertebrates (especially molluscs) in the low ppb (parts per billion) range.

It also has high phosphate at 0.53 ppm. You should have less than 0.03 ppm PO4 for a reef tank. Also, phosphate contributes to nuisance algae and nuisance cyanobacteria.

Your pH is high at 9.28 but that's because you have hard water. Your calcium and alkalinity are high but that's not a bad thing at all for water for a reef tank. You are obviously sitting over an ancient sea bed and your groundwater is coming up through ancient limestone.

Your tapwater would eventually cause problems (diatoms, nuisance algae and possibly cyanobacteria) for your aquarium if you were just treating it with drops and not running it through some sort of filtration.

Your little D.I. filter should be able to "fix" your water but I'm not sure how many gallons it can produce before the cartridge needs to be replaced. Be sure to run the water through it as slowly as possible.

This is what was claimed in the ad copy for your D.I. thingy:

Most aquarists produce somewhere between 50 and 150 gallons per cartridge.

If you are able to get 100 gallons per cartridge, that's 20 cents per gallon per each $20 cartridge, not counting shipping or the cost of the original thing. So Wal-Mart's water at 25 cents per gallon is a better deal.

Of course, you said you don't have access to Wal-Mart and it's a hassle lugging water home from Wal-Mart. Whether your Tapwater Filter will be cheaper in the long run than distilled water depends on how many gallons you get per cartridge and how long you stick with it.

In the long run, an R.O./D.I. filter system is cheaper and it produces much better quality water.

[good to goat]

Let me start out by saying that I am a RO/D.I. Tech. With 15 yrs experience. Water is a fascinating thing. It has to have things in to be right. What I'm saying is that it is a great place for minerals and gases and bacteria to live. Minerals in the form of ions, both positive and negative , has a atomic size to them. If you had a two tanks, one with salt water and one with tap water, and put a membrane between them and let them sit, over time the salt water will migrate to the tap water side to equal it self out. To put it simple, RO means reverse osmoses. Thats the opposite of osmoses[the transfer of a material though a membrane] by putting pressure on one side of the membrane you force the water through and not the ions. Making a purer water. Most RO's has a rejection rate of about 90%or better. Taking your tap water from a TDS of 150 to 15. This is were D.I. comes in, by ionic exchange, taking what ions are left in the water and swapping them with hydrogen atoms and oxogen atoms making the product pure H2O. Now remember I said that water likes to have stuff in it, it is now very aggressive to get minerals back[salt is good]. Now to say that you can drink it is just plain ignorant. RO water is safer yes but to say in any way that you can drink D.I. water is just not right and here is why. That pure of water is not in its natural state, it needs salts and minerals, were is it going to get it? Think of it as the opposite of gator aid, gator aid adds salts and minerals to your body and D.I. Water will take it out....I hope that answers your questions.

[Ninong]

You run through the D.I. stage only when you are producing water for your aquarium. It's okay to drink R.O./D.I. water but it's better if you just drink R.O. water. The explanation is way too lengthy for this discussion.

Looks like it's time to get into that discussion.

For starters, both R.O. water and R.O./D.I. water are not as healthy for you as water that contains minerals. That's because both contribute to electrolytic imbalance, which causes problems with neural transduction and muscle contraction. This is why, as has been pointed out by good to goat, athletes drink Gatorade and not R.O. water, or worse still, R.O./D.I. water, when they are engaged in strenuous activities.

When I said that "it's okay to drink R.O./D.I. water but it's better if you just drink R.O. water," I really meant that you shouldn't drink R.O./D.I. water but that drinking an occasional glass of it won't kill you. This came up a few years ago and the person asking the question was concerned because he had heard that drinking any amount of R.O./D.I. water could have deadly consequences.

If you were to take a TDS reading on that R.O. water from Walmart, you would probably get a reading of less than 10. That's really quite low, not as low as the zero to 1 ppm that you would expect after it passes through a five-stage R.O./D.I. filter but very low nonetheless. Obviously if the water has an extremly low TDS reading, you're getting nearly zero calcium, magnesium, potassium and other essential elements and microelements from the water. Fortunately, drinking water is not your only source of calcium, magnesium and other essential elements, and it's not your only source of fluids. The essential elements that would be missing from extremely low TDS water would be made up in the foods you eat.

If you are concerned and want to drink only the healthiest water, then avoid both R.O. water and R.O./D.I. water. Neither of them is healthy for you and certainly not as healthy as mineral water. In fact, don't put any water in your body unless it has a TDS reading of at least 75. Isn't that overdoing it? Sure, but that's what you should do it you want the healthiest possible water. Both R.O. water and R.O./D.I. water are essentially unhealthy for you and both would result in an overall negative electrolytic balance were they not adequately compensated from food.

As I said in my opening reply in this thread, the reason they make home R.O./D.I. units so that you can operate them with or without the D.I. canister is so that you don't drink R.O./D.I. water but drinking it won't kill you. Neither is really healthy for you but R.O./D.I. water is even more unheallthy than R.O. water. Both have to be compensated by food. Both take sodium and chloride out of your body.

[craqerjaq]

lol this thread took a different turn since I read it last...but hey you learn a little. I guess I'm just curious or assuming that spring water has all the good minerals for drinking? I like the stuff cause it doesn't taste like tap water and now knowing exactly where my water comes from and what's in it...tap water is something I don't want much of. It's coming from the Mississippi River...granted still in the early legs of it...but after a couple hundred miles there's plenty of nasty %$#@ in the water.

my cheap filter is in transit from CA to MN so one of these days here I'll be able to see how well it works. It will last me a while since my tank is full and I'll only be using it for the weekly water changes. I also grabbed 3 gals of distilled water when I stopped at the grocery store...I should check walmart one of these days and see if they are cheaper.

[Buckeye Field Supply]

If you had a two tanks, one with salt water and one with tap water, and put a membrane between them and let them sit, over time the salt water will migrate to the tap water side to equal it self out.

Not to be picky - but just so that folks don't get confused...

In the case above, the natural process of osmosis would have pure water moving FROM the pure water tank TO the salt water tank. That is, from an area of low solute concentration to an area of high solute concentration. Solute = whatever is dissolved in a solvent. In this case the solvent is pure water, and the amount of solute can be measured as TDS (in parts per million).

In reverse osmosis we change that natural direction of flow by adding pressure to the "dirty water side" of the membrane (our tap water) and force pure water from the "dirty water side" to the "pure water side" (of a semi-permeable membrane - i.e., our reverse osmosis membranes).

Clear as mud?

Russ

[Seige]

I use the 75g Typhoon 5
Aquarium Water | Reverse Osmosis | RODI Water | ReefKeeper Water | Typhoon 5 stage RODI Reefkeeper 75 GPD

TDS = 0 so I'm good. Wish it handled more then 75g per day. Taking 6 hours to fill a 20g tank seams like forever especially when the hose is layed out across the house.

Craqerjaq, you may want to order a TDS meter so you know how good your water is and when to change filters.
Aquarium Water | Reverse Osmosis | RODI Water | ReefKeeper Water | Dual TDS Meter Senno

[Carissa]

Maybe it was already mentioned but distilled is not the same as RO/DI. But it results in basically the same thing, pure water (or very close to it). Different process, basically the same result. I think distilled is maybe a bit more pure in general.

[Nemo Keeper]

Ok...so...if I were to use distilled water bought from a grocery store would I still need to add a dechlorinating agent to it before adding it to the tank?

F.Y.I Just read the label. It says..."Purified water...ozonated/purified by reverse osmosis!!!

[Carissa]

There should not be chlorine in distilled water, unless it was added to the water after distilling.

So based on that label it is not distilled, it is RO. No huge difference though. It's just two different processes of purifying water.

[Ninong]

Ok...so...if I were to use distilled water bought from a grocery store would I still need to add a dechlorinating agent to it before adding it to the tank?

No.

F.Y.I Just read the label. It says..."Purified water...ozonated/purified by reverse osmosis!!!

Well, that's certainly confusing. Distilled water is certainly purified water but it is not purified by reverse osmosis. It's purified by distillation. Two entirely different processes. If the label says "purified by reverse osmosis," then it's NOT distilled water and they have no business calling it distilled water.

You can use either distilled water or R.O./D.I. water. Distilled water usually sells for about 68-98 cents a gallon, making it rather expensive for use as the only water source for an aquarium.

Years ago it was possible that you might end up with distilled water that was produced using copper pipes but that's very unlikely nowadays.