DI resin longevity
- Thread starter guarda
- Start date
Yes, a lot of us do. Maybe I should have worded it differently. How long (about how many gallons) til your DI resin changes color? Got a tiny cyano patch yesterday and I'm thinking it's my ro/di.
OzoneParkGuy
New member
A+ on the TDS.. but to answer your question, it depends on how often your using your RODI.. usually mine lasts up to 3 months... color changing DI Resin.
MIKE NY
Two Decade club
one thing I've learned is don't change the filters or resin by time from someone else because everyone's water is different... dirtier water going in will be changed sooner and also the amount of water being made...as I mentioned measure the TDS coming out. I change my resin and filters together when the TDS reads 2
Last edited:
Buckeye Hydro
.Registered Member
A good rule of thumb is to replace your sediment filter and carbon block after six months. A more precise way to maximize the usable life of these two filters is to use a pressure gauge to identify when pressure reaching the membrane starts to decline. This is your indication one or both of the filters is beginning to clog.
Also be cognizant of the chlorine capacity of the carbon block. A good 0.5 micron carbon block for example will remove 99% of chlorine from 20,000 gallons of tap water presented at 1 gpm. Some original equipment suppliers commonly provide carbon cartridges rated at 2,000 to 6,000 gallons.
Regarding your RO membrane and DI resin, use your TDS meter to measure, record, and track the TDS (expressed in parts per million) in three places:
1. Tap water
2. After the RO but before the DI
3. After the DI.
The TDS in your tap water will likely range from about 50 ppm to upwards of 1000 parts per million (ppm). Common readings are 100 to 400 ppm. So for sake of discussion, let's say your tap water reads 400 ppm. That means that for every million parts of water, you have 400 parts of dissolved solids. How do we go about getting that TDS reading down to somewhere near zero?
If you do some experimenting with your TDS meter, you'll note that your sediment filter and carbon block filter (collectively called “prefilters”) do very little to remove dissolved solids. So with your tap water at 400 ppm, you can measure the water at the “in” port on your RO housing and you'll see it is still approximately 400 ppm.
The RO membrane is really the workhorse of the system. It removes most of the TDS, some membranes to a greater extent than others. For instance, 100 gpd Filmtec membranes have a rejection rate of 90% (i.e., they reject 90% of the dissolved solids in feed water). So the purified water coming from your 100 gpd membrane would be about 40 ppm (a 90% reduction). Filmtec 75 gpd (and below) membranes produce less purified water (aka “permeate”), but have a higher rejection rate (96 to 98%). The life span of a RO membrane is dependent upon how much water you run through it, and how dirty the water is. Membranes can function well for a year, two years, or more. To test the membrane, measure the total dissolved solids (TDS) in the water coming in to the membrane, and in the purified water (permeate) produced by the membrane. Compare that to the membrane’s advertised rejection rate, and to the same reading you recorded when the membrane was new. Membranes also commonly produce less water as their function declines.
After the RO membrane, water will flow to your DI housing. DI resin in good condition will reduce the 40 ppm water down to 0 or 1 ppm. When the DI output starts creeping up from 0 or 1 ppm, you know that your resin needs to be replaced. Sometimes people complain that their DI resin didn't last very long. Often the culprit is a malfunctioning RO membrane sending the DI resin “dirty” water. This will exhaust the resin quicker than would otherwise have been the case. Sometimes the problem is poor quality resin – remember that all resins are not created equal.
Russ
Also be cognizant of the chlorine capacity of the carbon block. A good 0.5 micron carbon block for example will remove 99% of chlorine from 20,000 gallons of tap water presented at 1 gpm. Some original equipment suppliers commonly provide carbon cartridges rated at 2,000 to 6,000 gallons.
Regarding your RO membrane and DI resin, use your TDS meter to measure, record, and track the TDS (expressed in parts per million) in three places:
1. Tap water
2. After the RO but before the DI
3. After the DI.
The TDS in your tap water will likely range from about 50 ppm to upwards of 1000 parts per million (ppm). Common readings are 100 to 400 ppm. So for sake of discussion, let's say your tap water reads 400 ppm. That means that for every million parts of water, you have 400 parts of dissolved solids. How do we go about getting that TDS reading down to somewhere near zero?
If you do some experimenting with your TDS meter, you'll note that your sediment filter and carbon block filter (collectively called “prefilters”) do very little to remove dissolved solids. So with your tap water at 400 ppm, you can measure the water at the “in” port on your RO housing and you'll see it is still approximately 400 ppm.
The RO membrane is really the workhorse of the system. It removes most of the TDS, some membranes to a greater extent than others. For instance, 100 gpd Filmtec membranes have a rejection rate of 90% (i.e., they reject 90% of the dissolved solids in feed water). So the purified water coming from your 100 gpd membrane would be about 40 ppm (a 90% reduction). Filmtec 75 gpd (and below) membranes produce less purified water (aka “permeate”), but have a higher rejection rate (96 to 98%). The life span of a RO membrane is dependent upon how much water you run through it, and how dirty the water is. Membranes can function well for a year, two years, or more. To test the membrane, measure the total dissolved solids (TDS) in the water coming in to the membrane, and in the purified water (permeate) produced by the membrane. Compare that to the membrane’s advertised rejection rate, and to the same reading you recorded when the membrane was new. Membranes also commonly produce less water as their function declines.
After the RO membrane, water will flow to your DI housing. DI resin in good condition will reduce the 40 ppm water down to 0 or 1 ppm. When the DI output starts creeping up from 0 or 1 ppm, you know that your resin needs to be replaced. Sometimes people complain that their DI resin didn't last very long. Often the culprit is a malfunctioning RO membrane sending the DI resin “dirty” water. This will exhaust the resin quicker than would otherwise have been the case. Sometimes the problem is poor quality resin – remember that all resins are not created equal.
Russ
DrHarryLopez
One Happy Reefer
i just ordered the Extreme Typhoon III 5 stage RODI.
This is the famous Typhoon III on steroids, bigger better, and with even more features.
TDS ALARM, DUAL PROBE IN-LINE EC AND HAND HELD DIGITAL TDS METERS.
150 GPD RODI Full size Color Changing mixed bed D.I.
This is the famous Typhoon III on steroids, bigger better, and with even more features.
TDS ALARM, DUAL PROBE IN-LINE EC AND HAND HELD DIGITAL TDS METERS.
150 GPD RODI Full size Color Changing mixed bed D.I.
cullyisgully
NYRC-LIRA
i just ordered the Extreme Typhoon III 5 stage RODI.
This is the famous Typhoon III on steroids, bigger better, and with even more features.
TDS ALARM, DUAL PROBE IN-LINE EC AND HAND HELD DIGITAL TDS METERS.
150 GPD RODI Full size Color Changing mixed bed D.I.
Nice Dr that looks like a grate pice to have.....:beer:
Awesome Harry. I think I'm going to just get a new rodi instead of buying a new membrane and filters. I'm getting 12-14 on the tds meter.
i just ordered the Extreme Typhoon III 5 stage RODI.
This is the famous Typhoon III on steroids, bigger better, and with even more features.
TDS ALARM, DUAL PROBE IN-LINE EC AND HAND HELD DIGITAL TDS METERS.
150 GPD RODI Full size Color Changing mixed bed D.I.
I have a typhoon rodi for over 6 years.I just replaced the membrane for first time and all filters(over a year).Just because i think they were overdue.
Di resin changed color 6 months ago and was still getting 0 tds.Confirmed inline meter is accurate with 2 handheld meters.
So whats the rule when to change?
Creaping TDS, or time.?
Di resin changed color 6 months ago and was still getting 0 tds.Confirmed inline meter is accurate with 2 handheld meters.
So whats the rule when to change?
Creaping TDS, or time.?
Buckeye Hydro
.Registered Member
see post 11 above
DrHarryLopez
One Happy Reefer
Funny thing is that oil changes for my car says the same thing 3,000 mile or time. I believe usage should have a lot to do with the changing out of the filters as well. I would say that I use about 320 gal of RO per month (50/week water change, ~4/day)
JMO
afernandez
Never Quit!!
I need to change out my carbons and di ..I was thinking of changing out my membrane even though my rodi is only 3 years old my tds is still 0.
Nice rodi Harry ! Makes mine look like a wimp :lol: mine is pretty basic (no pressure Gage or tds meters) I just have a basic 5stage 1 presediment 2carbons 100gpd membrane & the di ..
Mights just upgrade mine
Nice rodi Harry ! Makes mine look like a wimp :lol: mine is pretty basic (no pressure Gage or tds meters) I just have a basic 5stage 1 presediment 2carbons 100gpd membrane & the di ..
Mights just upgrade mine
afernandez
Never Quit!!
Mine is way under used... 15g a week * 4 times a month( 60g -/+ )
Buckeye Hydro
.Registered Member
It's your DI that brings it down to 0. Compare your RO water TDS to your tap water TDS to get a snapshot on how your membrane is working.
Similar threads
