How long do your RO/DI filters last?

vessxpress1 · 07/07/2007, 01:23 PM

I've had the Typhoon III for a full year now and it's still pumping out 0 TDS water. I use a large 50 gallon rubbermaid tub for storage so the flow rate really doesn't matter to me.

They say you're supposed to replace them at least after 12 months. Am I over working my RO membrane now? I know my sediment filter has gotten really brown. I have the filters and DI resin to replace with and ready to go.

I thought I'd see the TDS jump a little by now but it hasn't. I'm going to take a wild guess and say I've made approximately 700 gallons on this set of filters. Could be much less than that though.

Dubbin1 · 07/07/2007, 01:34 PM

When was the last time you calibrated your TDS meter?

kuoka · 07/07/2007, 02:30 PM

A lot depends on your water quality but I replace my filters (carbon, sediment, DI) every 6 to 7 mos and replace my RO membrane every 18 to 24 mos. I also use a flush kit which helps increase the life.

vessxpress1 · 07/07/2007, 02:37 PM

I flush the filters for 15 minutes every time before I use it. The line coming in to the tub has a small leak when the float valve shuts the system down so I have to close the ball valve once the tub's filled.

The TDS meter came with the unit and is only a year old also. It seems to be ok yet. It reads 0 on distilled water and my RO/DI water. If I test a jug that had a little magnesium or something mixed in it at one time, the water will read 40-50 TDS, after being filled with pure water. Tap still reads 286, same as when I got it.

CompNrdCR · 07/07/2007, 03:27 PM

I replace mine every 6 months... TDS meter reads out 380 going in and 0 going out...

melev · 07/07/2007, 08:41 PM

You want to replace them every six months. They are there to protect the membrane from chlorine damage. I just pulled mine out yesterday. My tap water is 172 (TDS) and the water was 2 TDS. The first sediment filter was quite golden like honey (originally it was white). The carbon was turning a slight shade of green, and reaked like a swimming pool of chlorine. The second carbon was still the original color, and smelled less of chlorine but you could smell it somewhat.

They were definitely not 6 months old, probably less.

Oh, and BTW due to massive rains in our part of Texas, the city is adding additional ammonia to keep the drinking water safe. Our systems can pull out some ammonia but not all of it if the levels are highly elevated. My tap water tested at .5 for Ammonia last week. The RO/DI tested 0.

It is wise to just replace the filters in January and July. The membrane should last 3 to 5 years that way. And flushing your system open for 15 minutes before collection is a little wasteful. 1 minute would be enough. If your unit is 100gpd, you just dumped 5+ gallons of water down the drain (RO water & waste water).

Dubbin1 · 07/07/2007, 08:49 PM

Quote:

Originally posted by melev
You want to replace them every six months.

That would depend on how much you use it.

melev · 07/07/2007, 08:51 PM

That's true. When I had only my 29g going, I used the same filters for 14 months. And when I finally did swap out the filters I couldn't believe how strongly the filters smelled of chlorine. It was so bad that I was really worried I was too late in getting them swapped out and that the membrane was likely damaged.

Fortunately I got to them in time, as I'm still using that same membrane and am approaching the 5 year mark. Changing them on a schedule really is the best way to not forget about it and they don't cost much.

vessxpress1 · 07/07/2007, 09:41 PM

Wow. Thanks for the info guys. I'm at 12 months now. The carbon blocks don't look bad but the initial sediment filter is very brown.

I really don't use mine as much as a lot of people. A full tub of water can last me about 2 months before I turn it on to fill it up again.

I have the filters on hand so I guess I'll just change them out now.

Buckeye Hydro · 07/08/2007, 06:06 AM

A good rule of thumb is to replace your sediment filter and carbon block after six months. A more precise way to maximize the useable 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. The Matrikx+1 (â€œChlorine Guzzlerâ€) for example will remove 99% of chlorine from 20,000 gallons of tap water presented at 1 gpm. 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 â€œinâ€ port on your RO housing and you'll see its 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 â€œpermeateâ€), but have a higher rejection rate (96 to 98%). The life span of a RO membrane is dependant 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 membraneâ€™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 to 3 ppm, 5 ppm, and higher, 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 â€œdirtyâ€ water. This will exhaust the resin quicker then would otherwise have been the case. Sometimes the problem is poor quality resin â€“ remember that all resins are not created equal!

Russ

vessxpress1 · 07/08/2007, 01:55 PM

Thanks for all the info. Yeah, I never tried testing just RO water out of it. The TDS never crept up coming out of the DI. All my water still read 0.

I took everything out just a little bit ago. As seen in another post, the sediment filter was shot. Probably should have been replaced a while ago.

The carbon blocks didn't look that bad and neither smelled like chlorine at all.

Kind of surprised.

The DI resin looked to be shot compared to the new. The new stuff is a dark blue and the old was a brown/yellow color.

Looks like I better start keeping track of how much I run through this thing.

07/07/2007, 01:23 PM	#1
vessxpress1 Premium Member Join Date: Aug 2005 Location: NW IL Posts: 1,603	How long do your RO/DI filters last? I've had the Typhoon III for a full year now and it's still pumping out 0 TDS water. I use a large 50 gallon rubbermaid tub for storage so the flow rate really doesn't matter to me. They say you're supposed to replace them at least after 12 months. Am I over working my RO membrane now? I know my sediment filter has gotten really brown. I have the filters and DI resin to replace with and ready to go. I thought I'd see the TDS jump a little by now but it hasn't. I'm going to take a wild guess and say I've made approximately 700 gallons on this set of filters. Could be much less than that though.

07/07/2007, 02:30 PM	#3
kuoka Premium Member Join Date: Mar 2005 Location: NorCal Cali Posts: 713	A lot depends on your water quality but I replace my filters (carbon, sediment, DI) every 6 to 7 mos and replace my RO membrane every 18 to 24 mos. I also use a flush kit which helps increase the life. __________________ They say don't talk about someone unless you've walked a mile in their shoes.. But if you do, at least you'll be ahead of them AND have their shoes! :) Current Tank Info: 72gal glass bow front reef, mostly LPS with some SPS, tangs, anthias, blenny, paired percula clowns, gold headed sleeper goby, red fairy wrasse

07/07/2007, 01:34 PM	#2
Dubbin1 Registered Member Join Date: Mar 2004 Location: Findlay, Ohio Posts: 11,540	When was the last time you calibrated your TDS meter?

07/07/2007, 02:37 PM	#4
vessxpress1 Premium Member Join Date: Aug 2005 Location: NW IL Posts: 1,603	I flush the filters for 15 minutes every time before I use it. The line coming in to the tub has a small leak when the float valve shuts the system down so I have to close the ball valve once the tub's filled. The TDS meter came with the unit and is only a year old also. It seems to be ok yet. It reads 0 on distilled water and my RO/DI water. If I test a jug that had a little magnesium or something mixed in it at one time, the water will read 40-50 TDS, after being filled with pure water. Tap still reads 286, same as when I got it.

07/07/2007, 03:27 PM	#5
CompNrdCR Premium Member Join Date: Sep 2005 Location: SF Bay Area Posts: 193	I replace mine every 6 months... TDS meter reads out 380 going in and 0 going out...

07/07/2007, 08:41 PM	#6
melev Moved On Join Date: Sep 2002 Location: Ft Worth, Tx Posts: 43,217	You want to replace them every six months. They are there to protect the membrane from chlorine damage. I just pulled mine out yesterday. My tap water is 172 (TDS) and the water was 2 TDS. The first sediment filter was quite golden like honey (originally it was white). The carbon was turning a slight shade of green, and reaked like a swimming pool of chlorine. The second carbon was still the original color, and smelled less of chlorine but you could smell it somewhat. They were definitely not 6 months old, probably less. Oh, and BTW due to massive rains in our part of Texas, the city is adding additional ammonia to keep the drinking water safe. Our systems can pull out some ammonia but not all of it if the levels are highly elevated. My tap water tested at .5 for Ammonia last week. The RO/DI tested 0. It is wise to just replace the filters in January and July. The membrane should last 3 to 5 years that way. And flushing your system open for 15 minutes before collection is a little wasteful. 1 minute would be enough. If your unit is 100gpd, you just dumped 5+ gallons of water down the drain (RO water & waste water).

07/07/2007, 08:51 PM	#8
melev Moved On Join Date: Sep 2002 Location: Ft Worth, Tx Posts: 43,217	That's true. When I had only my 29g going, I used the same filters for 14 months. And when I finally did swap out the filters I couldn't believe how strongly the filters smelled of chlorine. It was so bad that I was really worried I was too late in getting them swapped out and that the membrane was likely damaged. Fortunately I got to them in time, as I'm still using that same membrane and am approaching the 5 year mark. Changing them on a schedule really is the best way to not forget about it and they don't cost much.

07/07/2007, 09:41 PM	#9
vessxpress1 Premium Member Join Date: Aug 2005 Location: NW IL Posts: 1,603	Wow. Thanks for the info guys. I'm at 12 months now. The carbon blocks don't look bad but the initial sediment filter is very brown. I really don't use mine as much as a lot of people. A full tub of water can last me about 2 months before I turn it on to fill it up again. I have the filters on hand so I guess I'll just change them out now.

07/08/2007, 06:06 AM	#10
Buckeye Hydro .Registered Member Join Date: Sep 2006 Location: Cincinnati, Ohio Posts: 4,857	A good rule of thumb is to replace your sediment filter and carbon block after six months. A more precise way to maximize the useable 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. The Matrikx+1 (â€œChlorine Guzzlerâ€) for example will remove 99% of chlorine from 20,000 gallons of tap water presented at 1 gpm. 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 â€œinâ€ port on your RO housing and you'll see its 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 â€œpermeateâ€), but have a higher rejection rate (96 to 98%). The life span of a RO membrane is dependant 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 membraneâ€™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 to 3 ppm, 5 ppm, and higher, 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 â€œdirtyâ€ water. This will exhaust the resin quicker then would otherwise have been the case. Sometimes the problem is poor quality resin â€“ remember that all resins are not created equal! Russ

07/08/2007, 01:55 PM	#11
vessxpress1 Premium Member Join Date: Aug 2005 Location: NW IL Posts: 1,603	Thanks for all the info. Yeah, I never tried testing just RO water out of it. The TDS never crept up coming out of the DI. All my water still read 0. I took everything out just a little bit ago. As seen in another post, the sediment filter was shot. Probably should have been replaced a while ago. The carbon blocks didn't look that bad and neither smelled like chlorine at all. Kind of surprised. The DI resin looked to be shot compared to the new. The new stuff is a dark blue and the old was a brown/yellow color. Looks like I better start keeping track of how much I run through this thing.