trumph Posted June 15, 2007 Share Posted June 15, 2007 Just a general question for RO/DI users...at what number do you change your resins? I've been using my unit for over 2 years now and my TDS meter has just shown its first number over zero. Incoming tap water is rarely over 100 which contributed to the longevity of my resin. That, plus I only use 5 to 15 gallons a week. I expected to change out over a year ago. Changing out at anything under 10 seems extreme to me, even though 0 is optimal. Any opinions?? Link to comment
HecticDialectics Posted June 16, 2007 Share Posted June 16, 2007 Just a general question for RO/DI users...at what number do you change your resins? I've been using my unit for over 2 years now and my TDS meter has just shown its first number over zero. Incoming tap water is rarely over 100 which contributed to the longevity of my resin. That, plus I only use 5 to 15 gallons a week. I expected to change out over a year ago. Changing out at anything under 10 seems extreme to me, even though 0 is optimal. Any opinions?? my RO only is less than 10... I'd change it out once it started reading 1. I mean, you can buy some good quality resin for like $10. Is it really all that bad? Link to comment
Caesar777 Posted June 16, 2007 Share Posted June 16, 2007 You're talking the DI resin? I'd recommend replacing it fairly often, but that's just my experience. Make sure you change out the sed- and carbon- prefilters often enough, too. I see so many people come in with BROWN-ass prefilters, wondering why their "RO-thingy" won't work right. Link to comment
ezcompany Posted June 16, 2007 Share Posted June 16, 2007 once a year, or basically when your tds starts going up fast Link to comment
trumph Posted June 16, 2007 Author Share Posted June 16, 2007 I already have the replacement resin so I'll just change them out. I forgot about cleaning the other filters though. I'll have to backflush or remove them and rinse. Thanks for the reminder Caesar Link to comment
HecticDialectics Posted June 16, 2007 Share Posted June 16, 2007 I already have the replacement resin so I'll just change them out. I forgot about cleaning the other filters though. I'll have to backflush or remove them and rinse. Thanks for the reminder Caesar backflushing or rinsing won't clean carbon and sediment filters... you gotta replace them Link to comment
BuckeyeFieldSupply Posted June 18, 2007 Share Posted June 18, 2007 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 (“Chlorine Guzzler”) 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 “in” 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 “permeate”), 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 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 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 “dirty” water. This will exhaust the resin quicker then would otherwise have been the case. Sometimes the problem is poor quality resin – remember that all resins are not created equal! Russ @ BFS Link to comment
rottface4 Posted June 18, 2007 Share Posted June 18, 2007 So where is a good place to good for resin replacement? How can you tell a good resin from a poor one? Does anyone have recommendations for things such as filters, prefilter, membranes, resin? Link to comment
BuckeyeFieldSupply Posted June 18, 2007 Share Posted June 18, 2007 So where is a good place to good for resin replacement? How can you tell a good resin from a poor one? Does anyone have recommendations for things such as filters, prefilter, membranes, resin? Hmm... Do I know of a place that offers great service, has great RODI systems and supplies for great prices... Let me think... Link to comment
HecticDialectics Posted June 19, 2007 Share Posted June 19, 2007 Hmm... Do I know of a place that offers great service, has great RODI systems and supplies for great prices... Let me think... ^^ They actually do have very competitive prices on replacement filters/carbon/resin. I'd get the matrikx1 carbon cartridges and the 1 micron depth sediment filter. Then the color changing DI resin. It's only a few dollars difference between them and the crappier stuff, so you might as well get the high quality stuff. Link to comment
Abysswater Posted June 19, 2007 Share Posted June 19, 2007 So where is a good place to good for resin replacement? How can you tell a good resin from a poor one? Does anyone have recommendations for things such as filters, prefilter, membranes, resin? I've been using these guys for two years now, good pricing and customer service. This guy knows RODI filter systems like a mofo! http://www.airwaterice.com/ Link to comment
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