RO/DI Water Cost at Home

tcamos · 02/06/2014, 12:17 PM

Does anyone actually know how much a gallon of RO/DI costs them to make at home with a Spectrapure or BRS unit?

I'm curious if anyone has calculated the cost of unit, media, and wasted water to find out the per gallon rate.

I'm interested in a comparison between home costs and LFS costs.

Robb/Scottsdale/AZ · 02/06/2014, 01:04 PM

tagged for later.

interested to see how availability, transportation and scheduling, general "hassle", etc of getting water from the shoppe will be factored into the overall equation. I imagine there is a break over point for whether you are trying to maintain and service a 20 gallon reef or a 200 gallon reef as well

tcamos · 02/06/2014, 01:09 PM

In this case I'm willing to leave that out of the equation. The reason for that is because I go to the reef store for more than just water. I also go for enjoyment and other goods which in my view make the transportation cost balance out.

I am curious if anyone knows, based on their water bill, how much the wasted water actually costs them per gallon as a baseline.

schristi69 · 02/06/2014, 01:43 PM

Use the waste to water flowers and grass......no loss

ortie001 · 02/06/2014, 01:45 PM

Well, my girlfriend keeps VERY accurate accounting of our bills. In 2011 we paid about $1478 for the water bill. I had no aquariums set up that year. In 2012, we paid $1542, I set up 2, one is Sept., and the other in October. In 2013, I had 3 total systems, the 3rd was set up in early Jan., up and running for a total volume of about 410 gallons. We paid $1646 that year for our water bill.

I also have grass in my front and back yard, and plant winter and summer grass. I also tend to water my grass depending on the weather. So my "grass water" isn't the same every year. There was also a rate hikes in July,2012. However, I only went up 104$ from '12 to '13. To me, it's worth having my RO/DI system. I KNOW the TDS of my water. I know the last time the filters were changed. I know how long that water has been mixed. I also know what salt was used and what the SG is and all of my tank stay consistent. At any given time I have about 100 gallons of 0 TDS water ready to be used as top off or mixed for saltwater and I like that.

tcamos · 02/06/2014, 01:48 PM

Quote:

Originally Posted by schristi69

Use the waste to water flowers and grass......no loss

I know. However, no matter what someone does with it, drain or flowerbed it still has a dollar value per gallon. That's what I'm after.

Quote:

Originally Posted by ortie001

To me, it's worth having my RO/DI system.

Oh, I'm not doubting that at all, just trying to work out costs.

ortie001 · 02/06/2014, 02:07 PM

I didn't mention that I've started doing a daily 10 gallon water change on the two reef systems. The FOWLR gets a water change every two weeks.

tcamos · 02/06/2014, 02:12 PM

So I wonder how many gallons that $1646 bought you and how many of those gallons were for the tank.

See this is why I ask if anyone has done this. Like they have for electrical usage. It's a hard thing to figure out without planning in advance to figure it out.

ortie001 · 02/06/2014, 02:54 PM

Quote:

Originally Posted by tcamos

So I wonder how many gallons that $1646 bought you and how many of those gallons were for the tank.

See this is why I ask if anyone has done this. Like they have for electrical usage. It's a hard thing to figure out without planning in advance to figure it out.

Well, figure about 20-25 gallons for my tank, 10-15 for the girlfriend's, and 10-15 for the FOWLR every two weeks, and 5 gallons of top off each every 3-5 days. Given those numbers, on the low end 1820, and high end 2210.

Breadman03 · 02/06/2014, 03:46 PM

Honestly, my RODI is ridiculously cheap. I got a 98% rejection membrane from Spectrpure (they now have 99%) and I've made many hundreds of gallons of RODI for my tank plus many hundreds of gallons of RO for drinking water. The cost has got to be in the low pennies per gallon.

Mael · 02/06/2014, 04:29 PM

I believe most articles I have read says it can take 9months to a year for the unit to pay for itself vs store bought RO water.

I am debating which RO/DI unit to get right now and it will double as an RO tap for drikning water since I buy a 32 pack of bottled water once a week right now(I live alone, and like water

) so it should take me about 6-9months for the unit to pay itself off considering what I will use it for.

Also need to calculate replacement media for the system depending on how often you change it.

Unfortunately my numbers wont be accurate for anyone else, as I will use the RO water for drinking, brewing beer, and refilling my Keurig in addition to running full RO/DI for the reef. But I will keep track of my water bills and grocery bills to try and get a rough idea.

reefstew · 02/06/2014, 06:36 PM

I just purchased a 1000 gpd Spectrapure top of the line unit. The only advise I could give someone is what is your time & back worth? I have had tendonitis in my elbow from carrying tool buckets & now have nerve damage in my hand. Could be from 5 gal buckets of used water. Having your own unit does not even matter if it cost more & their is no way it could. I also spent a lot of money on my new unit so I could get a 1 to 1 waste ratio.

tcamos · 02/06/2014, 08:35 PM

Well, I'm not actually trying to figure out value. I'm trying to figure out cost per gallon.

This thread wasn't intended to be about is it worth it or not, that's part of figuring value.

I actually would like to know how many cents per gallon it costs someone to make it at home factoring in the cost of filter media and all the water used in the process.

If the media costs x dollars and produces 900 gallons before replacement I can do the math. If 900 gallons of actual water costs X dollars blah blah blah...

I know there are many reasons to get RO units for home, many of which are individual but what I don't know is how much per gallon actually comes out of the check book.

das75 · 02/06/2014, 09:43 PM

should easy enough the figure out. Check you current bill to work out cost/gal, and figure rodi typically produce at 4:1. So for every gallon in the tank, you're billed for 5g.

Buy filers by the case and see often less than $100 for 6 changes (and you change every 6 months), resin about $10 worth every 6 months.

Membranes can get 5 years so only additional pennies a gallon.

0

tcamos · 02/07/2014, 02:01 AM

5 years? Really! I didn't know that.

das75 · 02/07/2014, 08:04 AM

would be on the upper end but by changing your pre-filters regularly and flushing, yep

afishionado · 02/07/2014, 08:25 AM

Dependent on many variables ... Such as your level of knowledge/information on how to properly/efficiently run them to ensure longevity being crux/crucial.

Where you live, in Phoenix metropolitan, the (poor) source water quality will heavily determine the overall useful timeframe as well.

All said, under "ideal conditions", you should easily see 3+ yrs out of a high quality 75GPD membrane, such as the DOW Filmtec, running typical RO water usage rates for a ~100-150G system. HTH

tcamos · 02/07/2014, 10:25 AM

I'm not sure I'm diligent enough to get that kind of use out of it but it's nice to know it can be done. Maybe when I retire.

It's funny, when I posted this I was sure that someone had already figured it out by now. People know just how much electricity they use per pump per minute and for their lights so I figured they would have figured it out for water use as well.

das75 · 02/07/2014, 10:46 AM

as I pay $1.75/cubic meter (264g) for water, evapourating a couple of gallons a day and 55g water changes every 2-3 week, filters by the case and bulk resin, even without a calculator can realize water isn't that big of a concern compared to everything else in this hobby.

tcamos · 02/08/2014, 03:10 PM

Quote:

Originally Posted by das75

...even without a calculator can realize water isn't that big of a concern compared to everything else in this hobby.

I agree that's true but what I'm looking for here is the actual calculator but it looks like no one has actually done this like they have for electricity. I'll be first...how exciting.

saintsnsinners · 02/08/2014, 04:36 PM

Haha, I understand what you're trying to do Chad. it's kinda funny everybody has been posting everything but an actual answer to your question. I'd be curious as to what the answer is, as well. I think you'd have to find out how much you pay the city for water, first. then figure out how much it costs you to make a gallon or rodi water (cost of tap water to make a gallon of rodi.) then figure out material costs (filters, rodi unit cost, etc), per gallon. then you can compare that cost to store bought rodi. I believe the hard part is figuring out filter cost per gallon.

tcamos · 02/08/2014, 05:10 PM

I'm not sure if folks think I have some ulterior motive for asking but I don't. I really just want to know the cost per gallon people are spending using home units.

Since I don't own an RO unit I don't feel comfortable figuring filter cost per gallon which is one reason I asked here. The other reason is I honestly thought someone would just spit it right out because they already knew.

The arithmetic isn't terribly hard I just don't really have the number to plug into the formula.

das75 · 02/08/2014, 07:09 PM

Okay now you got me wondering...

So for monthly costs average over 3 years, assuming membrane changed once in the period, prefilters and resin every 6 months, water costs using rate in Edmonton, my 145g display evapourating 2g/day (though figure now less since changed to LEDs), 60g monthly change, 4:1 waste ratio

Membrane+prefilters+resin ($30+90+60)/36month = $5.00/month

$1.75/m^3/ 264 = $0.007/g x 600g/month = $4.20/month

So total cost water and filters $9.20/month.

Take it further, figure in unit cost and mine still going strong for close to 9 years; $150/108 say $1.40/month so total cost, all in, not having to hump bottles, for ro/di water I'm at $10.60 per month.

Basically 2 cent per gallon which is way cheaper than when I started this hobby using store bought ro/di

saintsnsinners · 02/08/2014, 07:11 PM

Quote:

Originally Posted by tcamos

I'm not sure if folks think I have some ulterior motive for asking but I don't. I really just want to know the cost per gallon people are spending using home units.

Since I don't own an RO unit I don't feel comfortable figuring filter cost per gallon which is one reason I asked here. The other reason is I honestly thought someone would just spit it right out because they already knew.

The arithmetic isn't terribly hard I just don't really have the number to plug into the formula.

Th problem is that the operating cost will be different for everybody. it will depend on your cost of tap water and how often you change membranes.

ortie001 · 02/08/2014, 07:56 PM

I wanted to be able to give you the answer, but I'm not sure if she kept the actual bill to get the cost per gallon. I gave you what I paid each month since I could open the spread sheet she keeps with bill amounts. Now, I'm a little more curious so I'm going to make sure I look at the next one so I can see for myself.

02/06/2014, 12:17 PM	#1
tcamos Reef, Crustacean, Puffers Join Date: Sep 2009 Location: East Mesa. Posts: 3,003	RO/DI Water Cost at Home Does anyone actually know how much a gallon of RO/DI costs them to make at home with a Spectrapure or BRS unit? I'm curious if anyone has calculated the cost of unit, media, and wasted water to find out the per gallon rate. I'm interested in a comparison between home costs and LFS costs. __________________ - Chad http://youtube.com/arizonafishkeeping Current Tank Info: 75 Gallon Reef & 20 Gallon Reef

02/06/2014, 01:09 PM	#3
tcamos Reef, Crustacean, Puffers Join Date: Sep 2009 Location: East Mesa. Posts: 3,003	In this case I'm willing to leave that out of the equation. The reason for that is because I go to the reef store for more than just water. I also go for enjoyment and other goods which in my view make the transportation cost balance out. I am curious if anyone knows, based on their water bill, how much the wasted water actually costs them per gallon as a baseline. __________________ - Chad http://youtube.com/arizonafishkeeping Current Tank Info: 75 Gallon Reef & 20 Gallon Reef

02/06/2014, 01:43 PM	#4
schristi69 Master of Space and Time Join Date: Aug 2005 Location: Glendale, AZ Posts: 1,340	Use the waste to water flowers and grass......no loss __________________ "Power tends to corrupt, and absolute power corrupts absolutely" - Lord Acton Current Tank Info: None, nada, gone

02/06/2014, 02:12 PM	#8
tcamos Reef, Crustacean, Puffers Join Date: Sep 2009 Location: East Mesa. Posts: 3,003	So I wonder how many gallons that $1646 bought you and how many of those gallons were for the tank. See this is why I ask if anyone has done this. Like they have for electrical usage. It's a hard thing to figure out without planning in advance to figure it out. __________________ - Chad http://youtube.com/arizonafishkeeping Current Tank Info: 75 Gallon Reef & 20 Gallon Reef

02/06/2014, 08:35 PM	#13
tcamos Reef, Crustacean, Puffers Join Date: Sep 2009 Location: East Mesa. Posts: 3,003	Well, I'm not actually trying to figure out value. I'm trying to figure out cost per gallon. This thread wasn't intended to be about is it worth it or not, that's part of figuring value. I actually would like to know how many cents per gallon it costs someone to make it at home factoring in the cost of filter media and all the water used in the process. If the media costs x dollars and produces 900 gallons before replacement I can do the math. If 900 gallons of actual water costs X dollars blah blah blah... I know there are many reasons to get RO units for home, many of which are individual but what I don't know is how much per gallon actually comes out of the check book. __________________ - Chad http://youtube.com/arizonafishkeeping Current Tank Info: 75 Gallon Reef & 20 Gallon Reef

02/06/2014, 01:04 PM	#2
Robb/Scottsdale/AZ Registered Member Join Date: Nov 2001 Location: Sun Lakes, AZ Posts: 143	tagged for later. interested to see how availability, transportation and scheduling, general "hassle", etc of getting water from the shoppe will be factored into the overall equation. I imagine there is a break over point for whether you are trying to maintain and service a 20 gallon reef or a 200 gallon reef as well

02/06/2014, 01:45 PM	#5
ortie001 Registered Member Join Date: Aug 2012 Location: Phoenix, AZ Posts: 130	Well, my girlfriend keeps VERY accurate accounting of our bills. In 2011 we paid about $1478 for the water bill. I had no aquariums set up that year. In 2012, we paid $1542, I set up 2, one is Sept., and the other in October. In 2013, I had 3 total systems, the 3rd was set up in early Jan., up and running for a total volume of about 410 gallons. We paid $1646 that year for our water bill. I also have grass in my front and back yard, and plant winter and summer grass. I also tend to water my grass depending on the weather. So my "grass water" isn't the same every year. There was also a rate hikes in July,2012. However, I only went up 104$ from '12 to '13. To me, it's worth having my RO/DI system. I KNOW the TDS of my water. I know the last time the filters were changed. I know how long that water has been mixed. I also know what salt was used and what the SG is and all of my tank stay consistent. At any given time I have about 100 gallons of 0 TDS water ready to be used as top off or mixed for saltwater and I like that.

02/06/2014, 02:07 PM	#7
ortie001 Registered Member Join Date: Aug 2012 Location: Phoenix, AZ Posts: 130	I didn't mention that I've started doing a daily 10 gallon water change on the two reef systems. The FOWLR gets a water change every two weeks.

02/06/2014, 03:46 PM	#10
Breadman03 New Old School Join Date: Feb 2012 Location: Luzerne County, PA Posts: 3,293	Honestly, my RODI is ridiculously cheap. I got a 98% rejection membrane from Spectrpure (they now have 99%) and I've made many hundreds of gallons of RODI for my tank plus many hundreds of gallons of RO for drinking water. The cost has got to be in the low pennies per gallon.

02/06/2014, 04:29 PM	#11
Mael Registered Member Join Date: Jan 2014 Location: Phoenix Posts: 1,351	I believe most articles I have read says it can take 9months to a year for the unit to pay for itself vs store bought RO water. I am debating which RO/DI unit to get right now and it will double as an RO tap for drikning water since I buy a 32 pack of bottled water once a week right now(I live alone, and like water ) so it should take me about 6-9months for the unit to pay itself off considering what I will use it for. Also need to calculate replacement media for the system depending on how often you change it. Unfortunately my numbers wont be accurate for anyone else, as I will use the RO water for drinking, brewing beer, and refilling my Keurig in addition to running full RO/DI for the reef. But I will keep track of my water bills and grocery bills to try and get a rough idea.

02/06/2014, 06:36 PM	#12
reefstew Registered Member Join Date: May 2009 Location: Phoenix ,Az Posts: 1,608	I just purchased a 1000 gpd Spectrapure top of the line unit. The only advise I could give someone is what is your time & back worth? I have had tendonitis in my elbow from carrying tool buckets & now have nerve damage in my hand. Could be from 5 gal buckets of used water. Having your own unit does not even matter if it cost more & their is no way it could. I also spent a lot of money on my new unit so I could get a 1 to 1 waste ratio.

02/06/2014, 09:43 PM	#14
das75 Registered Member Join Date: Oct 2002 Location: Edmonton AB Posts: 2,269	should easy enough the figure out. Check you current bill to work out cost/gal, and figure rodi typically produce at 4:1. So for every gallon in the tank, you're billed for 5g. Buy filers by the case and see often less than $100 for 6 changes (and you change every 6 months), resin about $10 worth every 6 months. Membranes can get 5 years so only additional pennies a gallon. 0 __________________ . Current Tank Info: 145g Starfire display (mixed reef) w/75g basement sump & 20g refugium, Barracuda return, Dart w/OM 4way CL, AI Hydras and Director.

02/07/2014, 02:01 AM	#15
tcamos Reef, Crustacean, Puffers Join Date: Sep 2009 Location: East Mesa. Posts: 3,003	5 years? Really! I didn't know that. __________________ - Chad http://youtube.com/arizonafishkeeping Current Tank Info: 75 Gallon Reef & 20 Gallon Reef

02/07/2014, 08:04 AM	#16
das75 Registered Member Join Date: Oct 2002 Location: Edmonton AB Posts: 2,269	would be on the upper end but by changing your pre-filters regularly and flushing, yep __________________ . Current Tank Info: 145g Starfire display (mixed reef) w/75g basement sump & 20g refugium, Barracuda return, Dart w/OM 4way CL, AI Hydras and Director.

02/07/2014, 08:25 AM	#17
afishionado Moved On Join Date: Sep 2013 Posts: 81	Dependent on many variables ... Such as your level of knowledge/information on how to properly/efficiently run them to ensure longevity being crux/crucial. Where you live, in Phoenix metropolitan, the (poor) source water quality will heavily determine the overall useful timeframe as well. All said, under "ideal conditions", you should easily see 3+ yrs out of a high quality 75GPD membrane, such as the DOW Filmtec, running typical RO water usage rates for a ~100-150G system. HTH

02/07/2014, 10:25 AM	#18
tcamos Reef, Crustacean, Puffers Join Date: Sep 2009 Location: East Mesa. Posts: 3,003	I'm not sure I'm diligent enough to get that kind of use out of it but it's nice to know it can be done. Maybe when I retire. It's funny, when I posted this I was sure that someone had already figured it out by now. People know just how much electricity they use per pump per minute and for their lights so I figured they would have figured it out for water use as well. __________________ - Chad http://youtube.com/arizonafishkeeping Current Tank Info: 75 Gallon Reef & 20 Gallon Reef

02/07/2014, 10:46 AM	#19
das75 Registered Member Join Date: Oct 2002 Location: Edmonton AB Posts: 2,269	as I pay $1.75/cubic meter (264g) for water, evapourating a couple of gallons a day and 55g water changes every 2-3 week, filters by the case and bulk resin, even without a calculator can realize water isn't that big of a concern compared to everything else in this hobby. __________________ . Current Tank Info: 145g Starfire display (mixed reef) w/75g basement sump & 20g refugium, Barracuda return, Dart w/OM 4way CL, AI Hydras and Director.

02/08/2014, 04:36 PM	#21
saintsnsinners Registered Member Join Date: Oct 2013 Posts: 451	Haha, I understand what you're trying to do Chad. it's kinda funny everybody has been posting everything but an actual answer to your question. I'd be curious as to what the answer is, as well. I think you'd have to find out how much you pay the city for water, first. then figure out how much it costs you to make a gallon or rodi water (cost of tap water to make a gallon of rodi.) then figure out material costs (filters, rodi unit cost, etc), per gallon. then you can compare that cost to store bought rodi. I believe the hard part is figuring out filter cost per gallon.

02/08/2014, 05:10 PM	#22
tcamos Reef, Crustacean, Puffers Join Date: Sep 2009 Location: East Mesa. Posts: 3,003	I'm not sure if folks think I have some ulterior motive for asking but I don't. I really just want to know the cost per gallon people are spending using home units. Since I don't own an RO unit I don't feel comfortable figuring filter cost per gallon which is one reason I asked here. The other reason is I honestly thought someone would just spit it right out because they already knew. The arithmetic isn't terribly hard I just don't really have the number to plug into the formula. __________________ - Chad http://youtube.com/arizonafishkeeping Current Tank Info: 75 Gallon Reef & 20 Gallon Reef

02/08/2014, 07:09 PM	#23
das75 Registered Member Join Date: Oct 2002 Location: Edmonton AB Posts: 2,269	Okay now you got me wondering... So for monthly costs average over 3 years, assuming membrane changed once in the period, prefilters and resin every 6 months, water costs using rate in Edmonton, my 145g display evapourating 2g/day (though figure now less since changed to LEDs), 60g monthly change, 4:1 waste ratio Membrane+prefilters+resin ($30+90+60)/36month = $5.00/month $1.75/m^3/ 264 = $0.007/g x 600g/month = $4.20/month So total cost water and filters $9.20/month. Take it further, figure in unit cost and mine still going strong for close to 9 years; $150/108 say $1.40/month so total cost, all in, not having to hump bottles, for ro/di water I'm at $10.60 per month. Basically 2 cent per gallon which is way cheaper than when I started this hobby using store bought ro/di __________________ . Current Tank Info: 145g Starfire display (mixed reef) w/75g basement sump & 20g refugium, Barracuda return, Dart w/OM 4way CL, AI Hydras and Director. Last edited by das75; 02/08/2014 at 08:01 PM. Reason: cost/g

02/08/2014, 07:56 PM	#25
ortie001 Registered Member Join Date: Aug 2012 Location: Phoenix, AZ Posts: 130	I wanted to be able to give you the answer, but I'm not sure if she kept the actual bill to get the cost per gallon. I gave you what I paid each month since I could open the spread sheet she keeps with bill amounts. Now, I'm a little more curious so I'm going to make sure I look at the next one so I can see for myself.