I replaced all of my Spectrapure RO/DI filters at the beginning of this year, including the membrane. I did not use Spectrapure brand for any of them, however, since I needed them right away and the LFS didn't have that brand. Afterwards, I made approximately 200-250 gallons of RO before my TDS started creeping, so I replaced the DI this past week. I had some left from a Dr. G's bag and although it didn't fill the canister where it was totally packed, it did fill it 80-90%. I was at 0 TDS till today. I have only made about 30 gallons of water and the TDS are now at 34. Total number of gallons made since replacing the DI has been less than 100. What's going on? Can it be that the DI resin was expired? I had the bag wrapped tightly with a zip tie and was in a dry, dark place. Or could it be that it wasn't filled enough? How many gallons should a DI canister yield anyway? I know it varies with the TDS coming in. Mine is usually at 328 before the membrane, and 9-10 after. Any insight from any RO/DI gurus much appreciated!
RO/DI acting weird
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Resin has short shelf life. Once opened it should either be completely used up or you should use a Seal a Meal type vacuum sealer and reseal the bag making sure it has a little moisture left in it. Store it in a cool dark place such as the back of the refrigerator so it stays moist. Once dried out it loses it cation and anion electrical properties.
You probably made an expensive mistake by getting in a hurry and not buying Spectrapure replacements. There really is a difference.
You probably made an expensive mistake by getting in a hurry and not buying Spectrapure replacements. There really is a difference.
Absolutely. Spectrapure is the only vendor to specially treat all their RO membranes with a process that is proven to improve their rejection rate. Even a 2% drop in rejection rate cuts your DI life in half which doubles you cost of treated water.
Why did you change the membrane? My membrane is 8.5 years old and still at better than 99.4% rejection rate. With that DI lasts over a year on a MaxCap DI and 3 years on a SilicaBuster DI with a tap TDS of 550-850 and a 100G reef with 30G sump and a 16G nano in Phoenix where I add a lot of make up water so it sees a lot of use.
You said your tap TDS is 328 and RO only is 9-10. Mine cuts it from 560 down to 2 with the Spectrapure membrane. You are at 97% rejection rate, I am at 99.6 and the membrane has never been touched in 8.5 years. That doesn't even address the differences in the DI resins which Spectrapure spends thousands of hours developing and testing, no one comes close on resin technology. They just came out with a new DI that should last twice as long as what I already have. Then they use 1 micron or smaller near absolute or absolute rated sediment filters which actually protect the pores in the carbon blocks so they can do their job. They are a unit or system from start to finish. If you don't protect the carbon it won't protect the RO which in turn won't protect the DI. Skimp anywhere in the process and it won't last as long nor perform as well.
Why did you change the membrane? My membrane is 8.5 years old and still at better than 99.4% rejection rate. With that DI lasts over a year on a MaxCap DI and 3 years on a SilicaBuster DI with a tap TDS of 550-850 and a 100G reef with 30G sump and a 16G nano in Phoenix where I add a lot of make up water so it sees a lot of use.
You said your tap TDS is 328 and RO only is 9-10. Mine cuts it from 560 down to 2 with the Spectrapure membrane. You are at 97% rejection rate, I am at 99.6 and the membrane has never been touched in 8.5 years. That doesn't even address the differences in the DI resins which Spectrapure spends thousands of hours developing and testing, no one comes close on resin technology. They just came out with a new DI that should last twice as long as what I already have. Then they use 1 micron or smaller near absolute or absolute rated sediment filters which actually protect the pores in the carbon blocks so they can do their job. They are a unit or system from start to finish. If you don't protect the carbon it won't protect the RO which in turn won't protect the DI. Skimp anywhere in the process and it won't last as long nor perform as well.
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zoanutty
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I was under the impression that the membrane needed changing every year. I was trying to be proactive, not cheap. But now that you have given me all his information I will order a refill kit from them, including the membrane and swap everything out once again. I wish there was some machine that would keep track of how many gallons have been yielded. I'm horrible at keeping count.
A Spectrapure membrane will easily last 5-7 years provided you protect it with no larger than a 1 micron near absolute rated sediment filter and matched 1 micron or smaller carbon block and monitor their condition and keep your waste ratio at what it should be for your exact unique water conditions. The absolute best thing you can do for a RO membrane is a water softener, if you do not have soft water and have ever considered it now may be the time. I fully expect to go 10+ years on my RO membrane so that is a huge cost savings over my old RO/DI from another vendor that lasted a maximum of 18-24 months per membrane.
I tried a residential water meter on my incoming water for a year or two but the flows are so small it wouldn't register much of it. Now I just keep track of how many times it fills my ATO container, I know it takes 11 measured gallons each cycle on and off the way I have placed the float switches.
I also keep a log book of everything I do to the RO/DI including periodic TDS, temperature and pressure readings, filter replacements, chlorine breakthrough, hardness, disinfection etc. You could write the number of buckets or trashcans you fill in something like that.
I tried a residential water meter on my incoming water for a year or two but the flows are so small it wouldn't register much of it. Now I just keep track of how many times it fills my ATO container, I know it takes 11 measured gallons each cycle on and off the way I have placed the float switches.
I also keep a log book of everything I do to the RO/DI including periodic TDS, temperature and pressure readings, filter replacements, chlorine breakthrough, hardness, disinfection etc. You could write the number of buckets or trashcans you fill in something like that.
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TbyZ
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When to change filters?
Firstly, the sediment filter. You should have a pressure guage as part of the unit. It will either be mounted to the RO housing, or be connected inline, prior to the water entering the RO membrane.
A pressure fall below your usual working pressure is an indication that the sediment filter is blocking up & restricting flow. When the water pressure falls below the specified requirement of the RO filter, its time to change it.
There is no other reason to change the sediment filter, & if using a town water supply, it should last quite a while.
Activated carbon filter. The main purpose of the carbon filter on an RO unit is to convert chlorine & chloramine to chlorides, & it does this by facilitating electron exchange, not by adsorption.
Keep in mind that when the carbon has reached it adsorption capacity (dissolved organics in town water supplies are rarely an issue) it will still function as an electron exchanger & convert chlorine & chloramine to chlorides. The exception being when there is channelling or total blinding of the carbon where direct contact with the carbon and chlorine is prevented.
When to change the carbon? Use a Total Chlorine test strip. Test your tap water first to get an indication of the it's level (make sure to run the tap for 5 minutes or so before taking doing test).
Test your units water at the carbon filter outlet. Make sure to let it also run for 5 to 10 minutes before testing. You should get a zero reading. If not, its time to change the carbon.
An RO membrane will remove at least 90% of TDS when new. Use a TDS hand held meter and take a test of the water at the RO outlet. When the percentage of TDS removed by the RO membrane falls below what it normally removes, they usually go down hill fast.
The DI should get the TDS to zero, or at the very least 99%. If the TDS reading taken at the DI outlet is equal to, or higher than the TDS reading taken at the RO outlet, the DI is way gone.
If you use you RODI unit intermittently, like I do, never let the RO membrane, or the DI resin go dry. They must be kept wet.
Hope this helps
TbyZ
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When you have finished using the unit disconnect some of the tubing and create a closed loop by joining the RO inlet & the DI outlet so no water leaks out.
What are you testing TDS with, where are you testing from and how are you testing it? Is the meter calibrated? Are you using a squeaky clean container to test in and are you triple rinsing with DI or distilled water between each sample?
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zoanutty
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Testing with this meter. Testing after DI. I collect a sample in a clean, dry glass cup, insert the meter and read it. I'll be honest, meter has not been calibrated, so that may be it. That's why I posted; cause I wanted to know what I was doing wrong.
