RO/DI resins..life span

trea718 · 03/24/2012, 04:25 PM

Possible Scenario:
Persons own tanks ranging from 75-100 gallons. Persons own RO/DI units that produce 75-100 gallons per day.

How long does the resin last in RO/DI units like the one mentioned in the scenario? Or how often do you guys change units that function like these?

Hamsternuts · 03/24/2012, 05:57 PM

The life of the DI resin is directly related to the TDS content coming out of the RO membrane. On my system, I get about 5 or 6 TSD after the RO stage and a DI canister last around 200 gallons or so.

DI resin gets replaced when the TDS coming out of it is more than zero. At least, at my house it does.

trea718 · 03/24/2012, 06:36 PM

Quote:

Originally Posted by Hamsternuts

The life of the DI resin is directly related to the TDS content coming out of the RO membrane. On my system, I get about 5 or 6 TSD after the RO stage and a DI canister last around 200 gallons or so.

DI resin gets replaced when the TDS coming out of it is more than zero. At least, at my house it does.

Thank you sir. Trying to get an idea of costs for a maintenance budget.

Cliff519 · 03/24/2012, 06:45 PM

For me, I get about 18 months. but that can depend on a lot of factors as well

But I have two stages of prefilter, two stages of carbon (one of them catalytic granular active carbon) all before the membrane. I use nothing but RO/DI water on both of my tanks (a 120 and a 90). The city I live in also uses chloramines in the water and the tap water has 190 to 200 ppm of TDS. All of these factors give me 18 months of use on a good quality RO membrane

I get about 2 ppm of TDS right after the membrain

DHyslop · 03/24/2012, 09:25 PM

Unless your water supply is downright terrible, the RODI will be the cheapest part of the tank to maintain if you shop around for filters. There's an LFS here that sells a prefilter for $10 and a DI cartridge for about $35. Or you can order from Bulk Reef Supply for $3 and $12.

Hamsternuts · 03/24/2012, 11:54 PM

My tap water runs about 400 TDS. So, i guess I'm getting just over 98% efficiency out of my membrane.

DI resin doesn't just instantly stop working. Even once all my resin changes color from blue to yellow showing that it's expended, I still get 1 PPM TDS coming out for quite a while. Who knows what that 1 ppm is, but its still less than the 5 or 6 going into the DI canister.

Playa-1 · 03/25/2012, 09:53 AM

How long does the resin last in RO/DI units like the one mentioned in the scenario? Or how often do you guys change units that function like these?
It depends on how much water you run thru the filter and the quality of the water going into the filter. It also depends on the filter itself. Some filters are more efficient then others and a more efficient filter will tend to prolong the life of some of the filters in the system.

yardboy · 03/26/2012, 10:06 AM

If you regenerate the resins, they last for years.

Buckeye Hydro · 04/02/2012, 04:21 AM

Because the OP didn't mention anything about the quality of their tap water or their RO water, really can't estimate how often you'll have to replace your DI resin. A rule of thumb would be about every 6 months you'll spend $12 on replacement resin.

Russ

yardboy · 04/02/2012, 04:28 AM

Quote:

Originally Posted by BuckeyeFS

Because the OP didn't mention anything about the quality of their tap water or their RO water, really can't estimate how often you'll have to replace your DI resin. A rule of thumb would be about every 6 months you'll spend $12 on replacement resin.

Russ

Time isn't a normal unit for an RO/DI system anyway. Throughput would be more pertinent. System designers use "grains/cu. ft." since resins have different capacities and feedwaters have different loads .

Buckeye Hydro · 04/02/2012, 05:47 AM

"Grains/cu ft." is good for softening resin, as the term "grains" is a measure of hardness.

In this case, if we knew RO water TDS, and we know resin capacity (we'd use the capacity of the resin we use at Buckeye), we can solve for the number of gallons that can be treated (if we make some other assumptions).

03/24/2012, 04:25 PM	#1
trea718 Registered Member Join Date: May 2005 Location: Maryland Posts: 150	RO/DI resins..life span Possible Scenario: Persons own tanks ranging from 75-100 gallons. Persons own RO/DI units that produce 75-100 gallons per day. How long does the resin last in RO/DI units like the one mentioned in the scenario? Or how often do you guys change units that function like these?

03/26/2012, 10:06 AM	#8
yardboy Advanced Bewilderment Join Date: Mar 2003 Location: Panama City Florida Posts: 563	If you regenerate the resins, they last for years. __________________ Ya gotta be tough, if you're gonna be stupid! Current Tank Info: 200g shallow cube, prop tank

03/24/2012, 05:57 PM	#2
Hamsternuts Registered Member Join Date: Dec 2011 Location: Tucson, AZ Posts: 137	The life of the DI resin is directly related to the TDS content coming out of the RO membrane. On my system, I get about 5 or 6 TSD after the RO stage and a DI canister last around 200 gallons or so. DI resin gets replaced when the TDS coming out of it is more than zero. At least, at my house it does.

03/24/2012, 06:45 PM	#4
Cliff519 Registered Member Join Date: Sep 2010 Location: Saskatoon, SK, Canada Posts: 189	For me, I get about 18 months. but that can depend on a lot of factors as well But I have two stages of prefilter, two stages of carbon (one of them catalytic granular active carbon) all before the membrane. I use nothing but RO/DI water on both of my tanks (a 120 and a 90). The city I live in also uses chloramines in the water and the tap water has 190 to 200 ppm of TDS. All of these factors give me 18 months of use on a good quality RO membrane I get about 2 ppm of TDS right after the membrain

03/24/2012, 09:25 PM	#5
DHyslop Registered Member Join Date: Sep 2005 Location: RI Posts: 1,085	Unless your water supply is downright terrible, the RODI will be the cheapest part of the tank to maintain if you shop around for filters. There's an LFS here that sells a prefilter for $10 and a DI cartridge for about $35. Or you can order from Bulk Reef Supply for $3 and $12.

03/24/2012, 11:54 PM	#6
Hamsternuts Registered Member Join Date: Dec 2011 Location: Tucson, AZ Posts: 137	My tap water runs about 400 TDS. So, i guess I'm getting just over 98% efficiency out of my membrane. DI resin doesn't just instantly stop working. Even once all my resin changes color from blue to yellow showing that it's expended, I still get 1 PPM TDS coming out for quite a while. Who knows what that 1 ppm is, but its still less than the 5 or 6 going into the DI canister.

03/25/2012, 09:53 AM	#7
Playa-1 Moved On Join Date: Jun 2007 Location: Laguna Niguel, CA Posts: 7,497	How long does the resin last in RO/DI units like the one mentioned in the scenario? Or how often do you guys change units that function like these? It depends on how much water you run thru the filter and the quality of the water going into the filter. It also depends on the filter itself. Some filters are more efficient then others and a more efficient filter will tend to prolong the life of some of the filters in the system.

04/02/2012, 04:21 AM	#9
Buckeye Hydro .Registered Member Join Date: Sep 2006 Location: Cincinnati, Ohio Posts: 4,857	Because the OP didn't mention anything about the quality of their tap water or their RO water, really can't estimate how often you'll have to replace your DI resin. A rule of thumb would be about every 6 months you'll spend $12 on replacement resin. Russ

04/02/2012, 05:47 AM	#11
Buckeye Hydro .Registered Member Join Date: Sep 2006 Location: Cincinnati, Ohio Posts: 4,857	"Grains/cu ft." is good for softening resin, as the term "grains" is a measure of hardness. In this case, if we knew RO water TDS, and we know resin capacity (we'd use the capacity of the resin we use at Buckeye), we can solve for the number of gallons that can be treated (if we make some other assumptions).