Roland Jacques
02-22-2008, 11:36 AM
Water $aver RODI (WS RODI) product review
This review is for the Water Saver type of RODI in general. You can build this yourself or buy this from “The filter guys”, and maybe others. http://www.thefilterguys.biz/water_saver_ro_di.htm (http://www.thefilterguys.biz/water_saver_ro_di.htm)
The Water Saver RODI is a 2 (or more) membrane in series RO adjusted to give the end result of 1 to 1 ratio of waste water to purified water. It works by taking the waste water from the first membrane and runs it through a second membrane. The 2 membrane flush in each membrane is adjusted close to 3:1 ratio. The 3 membrane I use is 4:1. Added together give an end result of a 1:1 ratio.
If you use a fair amount of water this may save you a good bit of money. Not mention helping out conserve water during our drought.
These numbers are base on Gwinnett county water prices water $3.66/1000 & sewer $4.52/1000.
The example I used is a high water user, 300 gallon a month. If you use 100 gallons cut the saving by 2/3…
Pros
1. WS RODI uses 60% less water.
If you use 300 gallons a month the WS-RODI will save you 10,800 gallons a year.
(It takes 1500 gallons to make 300 for normal ROD.I The WS RODI uses 600 gallons to make 300 )
Savings
$89 if you are on sewer
$40 if you’re on septic.
2. WS RODI passes 60% less water through your pre-filters.
Savings on Pre-filter usages is a little hard to judge. Because there’s so many different types of pre-filters. Pre-filters can cost between $10 - $60 per set. Some people change their pre-filter based on Time used, not gallons used, or pressure drop. I.M.O. 0.6 micron 20,000 gallon chlorine guzzler is a great pre-filter in protecting your RO and a great value per gallon. Some carbon block pre-filters are good for only 3000 gallons
Savings
$20-$40 per year
3. It makes water 60% faster.
(The 3 membrane unit I use makes water 100% faster.)
Savings
Time = $ ?
4. Efficiency (up front cost efficiency)
WS RODI will produce about 90% more water than a SM RODI, before replacing the membrane. Cost difference, ThefilterGuy’s WS RODI is $80 (50%) higher than their comparable Single Membrane SM RODI. The Water production is 90% more, than comparable SM RODI. If a properly maintained RO last 8 years. Divided by years of
Savings
About $10 a year
Total savings $70.00 - $139.00 per year
Xs 8 years life of RO membrane $560 -$1,112
The 8 year life time saving estimate keeps going after you change your membranes
CONS
1. Your purified water will have a 20% higher TDS.
You would have to spend 20% more on DI. So the TDS of my RO water right now is 1.0 TDS with a normal RO it would be 0.8 TDS. (You could not measure the difference with a normal TDS meter.)
Cost
$4 per year.
2. The second membrane may not last as long as a configuration normal RODI Membrane. The second membrane sees 20-30% higher TDS than a normal RODI will. But it also sees 20-30% less water. We can only guess as to how much shorter life it would have with Atlanta’s good water. But my guesstament is 10-20% less membrane life on the second membrane. Cost of membrane $50 losing 20% of life = $10 divided by years RO operation 8 years.
Cost
About $1 a year
Total extra cost $5 a year
Xs 8 years life of RO membrane $40
I’ve been using mine for 20 months and made 15,000 of pure water. It has saved me 45,000 gallons of water or $165 (no sewer cost). It also saves me about $60 on pre-filters. My septic system is Happy!
My TDS of my RO (before the DI) right now is less than 1ppm about 97% rejection. I use one 1 micron sediment $4 > one 0.2 sediment “Zeta Zorb” $25 > one Chlorine guzzler $11, plus shipping.
There was some skepticism as to how long the second or third membrane would last. So I over-built mine, to accurately test all aspects of this filter. After 20 months it is clear to me that the Pros far out weight the Cons. After 30,000 gallons through my WS RODI, my third membrane shows no sign of failing.
Even if you use as little as 50 gallons a month, and you are on a septic system, the WS RODI will pay for itself in the long run. I am comfortable in saying the Water Saver RODI works great. I think this is a good type of RO configuration for many reefers…, and I highly recommend it. And best of all you can DIY for about $60.
This review is for the Water Saver type of RODI in general. You can build this yourself or buy this from “The filter guys”, and maybe others. http://www.thefilterguys.biz/water_saver_ro_di.htm (http://www.thefilterguys.biz/water_saver_ro_di.htm)
The Water Saver RODI is a 2 (or more) membrane in series RO adjusted to give the end result of 1 to 1 ratio of waste water to purified water. It works by taking the waste water from the first membrane and runs it through a second membrane. The 2 membrane flush in each membrane is adjusted close to 3:1 ratio. The 3 membrane I use is 4:1. Added together give an end result of a 1:1 ratio.
If you use a fair amount of water this may save you a good bit of money. Not mention helping out conserve water during our drought.
These numbers are base on Gwinnett county water prices water $3.66/1000 & sewer $4.52/1000.
The example I used is a high water user, 300 gallon a month. If you use 100 gallons cut the saving by 2/3…
Pros
1. WS RODI uses 60% less water.
If you use 300 gallons a month the WS-RODI will save you 10,800 gallons a year.
(It takes 1500 gallons to make 300 for normal ROD.I The WS RODI uses 600 gallons to make 300 )
Savings
$89 if you are on sewer
$40 if you’re on septic.
2. WS RODI passes 60% less water through your pre-filters.
Savings on Pre-filter usages is a little hard to judge. Because there’s so many different types of pre-filters. Pre-filters can cost between $10 - $60 per set. Some people change their pre-filter based on Time used, not gallons used, or pressure drop. I.M.O. 0.6 micron 20,000 gallon chlorine guzzler is a great pre-filter in protecting your RO and a great value per gallon. Some carbon block pre-filters are good for only 3000 gallons
Savings
$20-$40 per year
3. It makes water 60% faster.
(The 3 membrane unit I use makes water 100% faster.)
Savings
Time = $ ?
4. Efficiency (up front cost efficiency)
WS RODI will produce about 90% more water than a SM RODI, before replacing the membrane. Cost difference, ThefilterGuy’s WS RODI is $80 (50%) higher than their comparable Single Membrane SM RODI. The Water production is 90% more, than comparable SM RODI. If a properly maintained RO last 8 years. Divided by years of
Savings
About $10 a year
Total savings $70.00 - $139.00 per year
Xs 8 years life of RO membrane $560 -$1,112
The 8 year life time saving estimate keeps going after you change your membranes
CONS
1. Your purified water will have a 20% higher TDS.
You would have to spend 20% more on DI. So the TDS of my RO water right now is 1.0 TDS with a normal RO it would be 0.8 TDS. (You could not measure the difference with a normal TDS meter.)
Cost
$4 per year.
2. The second membrane may not last as long as a configuration normal RODI Membrane. The second membrane sees 20-30% higher TDS than a normal RODI will. But it also sees 20-30% less water. We can only guess as to how much shorter life it would have with Atlanta’s good water. But my guesstament is 10-20% less membrane life on the second membrane. Cost of membrane $50 losing 20% of life = $10 divided by years RO operation 8 years.
Cost
About $1 a year
Total extra cost $5 a year
Xs 8 years life of RO membrane $40
I’ve been using mine for 20 months and made 15,000 of pure water. It has saved me 45,000 gallons of water or $165 (no sewer cost). It also saves me about $60 on pre-filters. My septic system is Happy!
My TDS of my RO (before the DI) right now is less than 1ppm about 97% rejection. I use one 1 micron sediment $4 > one 0.2 sediment “Zeta Zorb” $25 > one Chlorine guzzler $11, plus shipping.
There was some skepticism as to how long the second or third membrane would last. So I over-built mine, to accurately test all aspects of this filter. After 20 months it is clear to me that the Pros far out weight the Cons. After 30,000 gallons through my WS RODI, my third membrane shows no sign of failing.
Even if you use as little as 50 gallons a month, and you are on a septic system, the WS RODI will pay for itself in the long run. I am comfortable in saying the Water Saver RODI works great. I think this is a good type of RO configuration for many reefers…, and I highly recommend it. And best of all you can DIY for about $60.