TonyInVa November 27, 2009 Share November 27, 2009 I am new to TDS meters. I know the goal is to have a 0.0 reading. I tested and got 020 ppm. I don't know how bad that is. Link to comment Share on other sites More sharing options...
Coral Hind November 27, 2009 Share November 27, 2009 What kind of water are you testing, Tap, RO, or DI? Link to comment Share on other sites More sharing options...
TonyInVa November 27, 2009 Author Share November 27, 2009 RO/DI Link to comment Share on other sites More sharing options...
davelin315 November 27, 2009 Share November 27, 2009 You should test at the source, before the RO membrane, then after the RO membrane, and then again after the DI stage. Most membranes have a rejection rate of about 90-97%, so you're shooting for pretty close to that for after the membrane (give or take a bit as the carbon filters can actually increase your TDS). There are a few things that can cause it to not run at optimal levels, including water pressure and water temperature (if your cold water is too cold, you can coil up the tubing before the unit in a bucket with a heater in it to warm it up a bit), but if you're within that range your filter is running pretty well. Also test after the DI stage as you're doing. I find that if it hasn't been running for a bit, sometimes some of the used up resin will put some things back into the water and so you have to let it run until those are cleared. As far as what's good and what's not, you never know really what you're filtering out or letting through. If the DI resin is spent, it could be releasing contaminants back into your water. If the membrane is shot, try back or fast flushing it to clean it up a bit and then retest. Link to comment Share on other sites More sharing options...
TonyInVa November 27, 2009 Author Share November 27, 2009 At the source the readings are 161 ppm. The problem I am having is I am not sure if RO/DI is hooked up properly. Link to comment Share on other sites More sharing options...
Jon Lazar November 27, 2009 Share November 27, 2009 At the source the readings are 161 ppm. The problem I am having is I am not sure if RO/DI is hooked up properly. Your system should be working better than this. You really need to figure out whether you have everything hooked up correctly first. Link to comment Share on other sites More sharing options...
TonyInVa November 27, 2009 Author Share November 27, 2009 Your system should be working better than this. You really need to figure out whether you have everything hooked up correctly first. This is how I have it hooked up. http://www.waterforliving.com/Install_Diagram.gif I have seen diagrams were it goes through the membrane first. I have also seen diagrams where it goes through the first two canisters and then carbon last. Not sure which way is correct. Link to comment Share on other sites More sharing options...
TonyInVa November 28, 2009 Author Share November 28, 2009 Anyone have a link to a diagram that has propper 6 Stage RO/DI installation. Link to comment Share on other sites More sharing options...
Jon Lazar November 28, 2009 Share November 28, 2009 Anyone have a link to a diagram that has propper 6 Stage RO/DI installation. This is for two RO membranes, but the idea is the same for one. Water flows through sediment filter first, then carbon, then membrane, then DI. Link to comment Share on other sites More sharing options...
davelin315 November 28, 2009 Share November 28, 2009 What system is this? This looks to be a drinking water system, are you sure it's an RO/DI and not just an RO system? The last stage, 26, in a drinking water system would be a carbon filter for taste, not for DI. The way you've got it installed is correct as you want to go through pre-filter to remove sediment, then either GAC to carbon block or carbon block to carbon block (depends on what's in your water, ammonia and chlorine or chloramine, generally GAC to carbon block is preferred based on alternating use by most municipalities), then to the RO membrane, then out to a DI. In a purely drinking water situation there's no DI as it leaves the water totally tasteless, which some people don't like, so there's a final carbon filter that actually will add back to the water and "improve the taste" of the water. DI for a fish tank is a final polishing step that removes any residual TDS from the product water. If this isn't the case, then something is worn out in the system or the PSI or water temperature is affecting it. Link to comment Share on other sites More sharing options...
TonyInVa November 28, 2009 Author Share November 28, 2009 What system is this? This looks to be a drinking water system, are you sure it's an RO/DI and not just an RO system? The last stage, 26, in a drinking water system would be a carbon filter for taste, not for DI. The way you've got it installed is correct as you want to go through pre-filter to remove sediment, then either GAC to carbon block or carbon block to carbon block (depends on what's in your water, ammonia and chlorine or chloramine, generally GAC to carbon block is preferred based on alternating use by most municipalities), then to the RO membrane, then out to a DI. In a purely drinking water situation there's no DI as it leaves the water totally tasteless, which some people don't like, so there's a final carbon filter that actually will add back to the water and "improve the taste" of the water. DI for a fish tank is a final polishing step that removes any residual TDS from the product water. If this isn't the case, then something is worn out in the system or the PSI or water temperature is affecting it. This is the system I have. http://jimstrains.com/?mainURL=/store/item...PD_6_stage.html I believe the post carbon filter is more for drinking. Link to comment Share on other sites More sharing options...
cabrego November 28, 2009 Share November 28, 2009 This is the system I have. http://jimstrains.com/?mainURL=/store/item...PD_6_stage.html I believe the post carbon filter is more for drinking. Well, the website gives you the order of the filters..what is the problem? Is it in the order shown in the website i.e., stages 1-6? If so, how long has this been running? It is possible your DI resin has been exhausted. A TDS of 20 with source water of is a rejection rate of about 88% which is well below the rated efficiency of standard membranes. This does not necessarily mean your membrane or filters are bad. Are you using the drinking water reservoir? Assuming your system is setup correctly, which you should verify, TDS can creep in your water in many different ways. Give more information and I will try to help you more. Link to comment Share on other sites More sharing options...
davelin315 November 28, 2009 Share November 28, 2009 I would ditch the post filter, that's most likely adding back to your system, and then I would downsize the micron rating on the first filter and get a 10 micron filter followed by GAC (looks like yours might be a carbon block) in the 2nd stage, then replace the 3rd stage with the 1 micron prefilter with a chlorine guzzler (rated at .1 micron nominal) and then go into your membrane followed by the DI. Also, looks like the membrane is a TFE, which I seem to recall is inferior to TFC, but I can't remember the rationale. With the units from that place, it also says up to 99% rejection rate on the membrane, but I believe that the majority of 100gpd membranes are only at around 90% rejection or less whereas a 75gpd membrane is at around 97% or so. Seems like you have a serviceable unit, just not what most are looking for in terms of reef tanks and aquarium grade water. Link to comment Share on other sites More sharing options...
Buckeye Field Supply February 4, 2010 Share February 4, 2010 Did you get this system suared away? Russ Link to comment Share on other sites More sharing options...
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