Is RODI really more expensive?

[disc1]

There reason to not drink off your RODI has nothing to do with minerals. The water past the first carbon stage has very little or no chlorine left. Bacteria, potentially pathogenic bacteria, can grow in that and build up a violin in your lines. Slim chance of it biting you, but that's the reason they recommend against it. It's nothing to do with minerals. RODI can't take minerals away from you. Where would it take it?

 

[hilgert]

I will defer to disc1’s statements...my bad for letting myself fall into the trap of an off-topic discussion.

 

[Bent]

I will defer to disc1’s statements...my bad for letting myself fall into the trap of an off-topic discussion.

I'm not trying to prove you wrong or belittle you to serve my own ego. Don't defer to anyone else's statements. Do your own research, draw your own conclusions based on the best information you can find and don't let ANYONE tell you what to think, ever.

 

[hilgert]

I'm not trying to prove you wrong or belittle you to serve my own ego. Don't defer to anyone else's statements. Do your own research, draw your own conclusions based on the best information you can find and don't let ANYONE tell you what to think, ever.

That's good advice, and I'll assume positive intent in having BS called on my post. I'll still value the view of disc1, whom I consider a good source of information.

Anyway, back to the topic of the thread. I believe the conclusion that I have drawn, based on my own research and the best information I can find, is correct...RODI is not really that expensive relative to the total cost of the hobby (the possible exception being smaller tanks, of which there are certainly many).

 

[Bent]

That's good advice, and I'll assume positive intent in having BS called on my post. I'll still value the view of disc1, whom I consider a good source of information.

Anyway, back to the topic of the thread. I believe the conclusion that I have drawn, based on my own research and the best information I can find, is correct...RODI is not really that expensive relative to the total cost of the hobby (the exception being smaller tanks, of which there are certainly many).

It was an attempt at being positive. I've had a bit to drink today and my filter tends to drop, but I would never say something online to someone I would not say to their face. So :beer: no worries my friend.

So yes back on topic, I can agree with that statement.

 

[Vilas]

Well, I live by the sea, and my tap water is salty and pretty much undrinkable, so we installed an RO unit regardless of the tank.
For drinking water, I've been dissolving cal mag (calcium and magnesium tablets) into a 5l container.
Would you all think this would help the lack of minerals, or would it be a waste? Or should I readd a small amount of our mineral rich tap water? It is safe to drink, just doesn't taste right.

Sorry to derail, I've been meaning to get opinions on this, thought I'd jump in while the topic is being discussed.

And for us, yes, it is a thousand times cheaper. We were spending $4/day on bottled water!
Paid for itself in just over a month, tank aside.

 

[Buckeye Hydro]

Is it simple to plumb a rodi unit to also have an ro output? I currently buy ro water for my water cooler and get it very cheaply at $.20/gallon and I am now planning to start a reef tank and was hoping to convince the wife that a rodi unit will save us money and the hassle of buying jugs of ro water for the cooler as well.

Yes - Simple if you ask for help from someone who knows what they're talking about. Be aware that there are a lot if mis-plumbed systems out there.

Russ

 

[Coach Vince]

wow... I just read an internet battle over water... I'm not sure what else there is to do now. I think I've seen it all :lol:

 

[kmbyrnes]

http://www.reefcentral.com/forums/showthread.php?t=2399701

I live in Mesa, AZ. These figures are from my Jan 2014 bill.

Total water charges including sewer,fees and taxes: $58.02
Total billed gallons: 9000
Cost per gallon of billed water: 0.64 cents per gallon.
Assuming a 4:1 ratio and 100% waste,my cost per RO/DI gallon in Mesa is 3.2 cents. Most LFS charge 10-30 times that for RO/DI,
The value is what you make of it in time,travel, and extra effort.

I paid about $150.00 for a BRS 4-stage system last October.
If you use the low end of 33 cents per gallon for purchased RO/DI, the unit payback point is at 454 gallons.

I use about 25 gallons per week for all our tanks.
If you ignore the approximately 300 gallons for initial setup and cycling of my 110g DT + 30g sump, it will have paid for itself in less than 5 months.
If you count the setup water, it's already paid for itself and my tank has only been cycled for 2 months!

My back already thanks me!

 

[Buckeye Hydro]

If you are able to put your concentrate (a.k.a. "waste water") to use, you'll hit the break even point even sooner.

Russ

 

[Buckeye Hydro]

Having watched over the years (and with some amusement) many people lugging 5-gallon containers of RODI/saltwater out of fish stores, I thought I'd lay out some math on on the cost of RODI in the hopes that a few pocketbooks may benefit.

Assumptions:

• A decent new RODI (which INCLUDES an initial set of filters) is $170. Here is what I would get if I were buying a new system today:
  BRS 4 Stage Value PLUS RO/DI System - 75GPD
  Note that this INCLUDES the first set of filters and an inline TDS meter.
• RODI filters/cartridges last for about 1000 gallons of finished RODI water (mine last much longer, but just assuming 1000 gallons for this exercise).
• The cost for replacing sediment filter, carbon block and DI is about $40 per set (you can spend less or more).
• RO membrane (the real "heart" of the system) lasts for 5000 gallons of finished RODI (these can last MUCH longer if flush regularly...but assuming 5000 gallons this for this exercise).
• The cost of a new RO membrane is $50 (you can spend less or more).
• Excluding cost of tap water into the RODI (this can vary from practically nothing to a lot...for me it's something I don't care about).
• "Average" tap water conditions...some people may have much better tap water (RODI stuff will last longer), while others may have much worse tap water (RODI stuff will need replacing sooner).
• This is based on my experience using RODI at several places I've lived in the US (When I measured today my TDS was 383...I've seen it up to 450 and down to 280). For ME these numbers are conservative...I get a lot more mileage out of my RODI system than the assumptions I am making above.

Cost for the FIRST 5000 gallons of finished RODI water:

• RODI system - $170.
• Filter/cartridge replacements - $160 (4 replacements at $40 each).
• Total cost for 5000 gallons of RODI - $330
• Cost per gallon: $0.07 (rounding up).

Cost for the NEXT 5000 gallons of finished RODI water:

• Filter/cartridge replacement - $200 (5 replacements at $40 each).
• RO membrane replacement - $50.
• Total cost for 5000 gallons of RODI: $250.
• Cost per gallon: $0.05.

So, even if one were to double the cost of the system/filters ($340/$80), and halve the amount of RODI water produced (2500 gallons), that's still $0.27 (rounded up) and $0.20 respectively.

For smaller systems (nano tanks and the like) perhaps an RODI system would be overkill (a long payback period, or an unwanted use of space for a small system), and LFS store-bought RODI might be a better approach (but please, not tap water...I beg you). My opinion is that if you have a good water change schedule, and have a tank that is 50 gallons or larger, you would be well-served by owning your own RODI system rather than paying someone else 10X the cost (plus the fuel cost to/from the store).

So, what's really the cost of an RODI system? Almost free, relative to all the other expenses in this hobby (tanks, lights, pumps, fish, corals, rocks, leaks, fights with spouse, etc.). A nickel per gallon...and no fuel/time spent going to/from the LFS. Essentially, the annual cost (with the math above) is about the cost of one fish or coral (that proper water might save).

Ever wonder why almost no fish stores sell RODI systems, and why they are so happy to help you with your RODI water refills? I've actually had this discussion with some LFS owners over the years, and the answer is always "Why would I want to sell RODI systems when I can sell water at 10X what it costs me to make." Every time I see folks going in/out of LFS with jugs of water I picture the LFS owner laughing (that Dr. Evil laugh from Austin Powers).

The other variable to throw in here would be using your RODI to produce RO drinking water, and the cost savings relative to buying bottled water. I never have understood why more reefers don't do this.

Russ

 

[Sugar Magnolia]

If you are able to put your concentrate (a.k.a. "waste water") to use, you'll hit the break even point even sooner.

Russ

Yep. My waste line goes into my washing machine when I make rodi.

 

[Victorg1001]

The convenience of having my own RODI water at home makes the math not even worth doing for me. LFS could give the water away and I still would have purchased my own RODI unit.

 

[Buckeye Hydro]

Yep. My waste line goes into my washing machine when I make rodi.

Same here

 

[dkeller_nc]

http://www.reefcentral.com/forums/showthread.php?t=2399701

I live in Mesa, AZ. These figures are from my Jan 2014 bill.

Total water charges including sewer,fees and taxes: $58.02
Total billed gallons: 9000
Cost per gallon of billed water: 0.64 cents per gallon.

Umm - your math appears to be a bit off. $58.02/9000 gallons is 0.65 cents per gallon. That's still extraordinarily expensive for treated municipal tap water, but I'm guessing the service in AZ is considerably more than it is in the Eastern US. Many municipalities measure and bill for water in units of cubic feet (without explicitly stating that on the water bill), and also add in substantial taxes. In my case, only about 20% of the "water bill" is actually for water.

 

[dkeller_nc]

For drinking water, I've been dissolving cal mag (calcium and magnesium tablets) into a 5l container.
Would you all think this would help the lack of minerals, or would it be a waste? Or should I readd a small amount of our mineral rich tap water? It is safe to drink, just doesn't taste right.

I'd be cautious about adding calcium and magnesium to your drinking water unless you know the exact amount of Ca/Mg in the tablets, and are careful not to exceed what would be a reasonable tap water concentration. It's actually possible to over-do calcium intake in particular, and it has undesirable potential health effects.

If you water truly is salty (excess sodium chloride), that would be bad as well if someone has high blood pressure. But if the sodium content is less than 20 ppm, the "taste" aspect of it might be something different altogether. Might be worth experimenting by tapping off the output of your carbon filter and doing a taste-test.

 

[dkeller_nc]

I will defer to disc1's statements...my bad for letting myself fall into the trap of an off-topic discussion.

Don't feel too bad. The "don't drink RO/DI water" thing has been frequently repeated in the echo chamber of the internet. There are even scientists that lack fundamental physical chemistry knowledge that repeat this foolishness.

In particular, there's a W.H.O. publication titled "Health Risks from Drinking Demineralised Water" that uses breathtakingly incorrect and inappropriate reasoning, as well as highly suspect epidemiological studies, to conclude that humans shouldn't drink purified water.

There is only one correct conclusion in the paper - that distributing pure demineralized water through a typical municipal drinking water piping system is inadvisable because of the possibility of leaching heavy metal contamination from the (old) piping and because of potential system sepsis from the lack of chlorine.

To be honest, I really don't understand why many, if not most, scientists that don't have expertise in the field nonetheless think it's OK for them to draw conclusions about purification systems and/or the finished product used for laboratories and manufacturing. Yet they wouldn't make the same assumptions about their knowledge in almost any other aspect of the hard sciences outside their particular expertise.

I've encountered it frequently - the Director of one particular CDC lab responsible for certification of state laboratories for detection/analysis of chemical terrorism agents insisted that the required purified water used for dilution of samples and preparation of mobile phases for chromatography needed to meet a resistivity standard that exceeded the theoretical maximum for completely pure water.

Note the "theoretical" adjective - water of that purity has never actually been produced on the planet Earth by any method. And the standard methods from that same CDC laboratory required using that same impossibly-pure water in normal laboratory glassware. The simple act of pouring such high purity water into glass results in great deal of contamination. Still more than suitable for analytical chemistry, but far, far removed from the Director's purity expectations.

 

[Buckeye Hydro]

I try to avoid this "health issue" discussion for just that reason. I'm not a doctor, and I'm not a chemist. I can point people to technical papers, but in most cases that's not what they are interested in.

The most practical advise on the topic of drinking RODI water, IMO, is:
1. It is very expensive to make RODI water (relative to just RO water).
2. DI, or RODI water doesn't taste good/right. Many times if I see people saying "RODI water tastes great - been drinking it for years", we find they are using a mis-plumbed ebay system that routes the DI water through GAC.:rolleye1:

Russ

 

[dkeller_nc]

DI, or RODI water doesn't taste good/right. Many times if I see people saying "RODI water tastes geate - been drinking it for years", we find that they are using a mis-plumbed ebay system that routes the DI water through GAC.:rolleye1:

IMO, this is one of the better reasons not to drink RODI - it tastes like crap. And - wait for it - there's not a thing wrong with drinking plain ol' municipal tap water unless it also tastes like crap because of an elevated sulfer concentration.

My only concession to "treating" my drinking water is putting it in a glass milk bottle in the fridge so that it's cold.

 

[Tom39]

Cost savings with a reef tank? Isn't that an oxymoron?
When the day comes that I start to justify the cost of an item for my system, that's the same day that I know it is time to get out.
I have a AquaFX RODI, in which I have added the following: 2 dual in-line TDS meters, a dual DI kit, a piggyback 100gpd RO and god only knows how much at the hardware store for 1/4" fittings and that is not counting the cost of water or replacement filters. The total system costs over $500 and makes 0 TDS water. Could I do it cheaper? Or courses I could have. And don't get me wrong, there should always be a budget that is not exceeded. But this hobby is not about saving money or if you don't get the sh#ts from drinking RODI. It's about making the best environment you can for the responsibly you have accepted for the life in your tanks.

But IMO, if you are counting pennies and cheaping out on the thing that makes up 90% (water) of your system. You're probably the kind of person that buys cigarettes, beer and lottery tickets and then tells your kid they can't get new socks because you don't have any money such frivolous items.

Right or wrong, that's my $0.02

Tom