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  1. AquaFX

    New RO/DI Unit

    Sounds like the DI may be exhausted. Or the meter is out of calibration! :) But upon exiting the RO/DI system look to be around 0 ppm. Especially when considering your incoming water to be at 130 ppm!!! As a side note you should not be any higher than 13-15 ppm leaving your RO membrane...
  2. AquaFX

    Reverse Osmosis & Deionization

    The GAC filters can be coconut based or carbon based, it should not matter, carbon removes "liquid" containments. It may alter the TDS a little, due to the conductivity of different contaminates The fact that the unit was not used and sat for so long, is more likely the culprit. Membranes...
  3. AquaFX

    Reverse Osmosis & Deionization

    Aso Every time the water "sits" on the membrane without sufficient pressure to over come naturally occurring osmosis, TDS creep occurs. Osmosis in a naturally occurring phenonamonm; we REVERSE osmosis by applying a pressure (that is greater than the naturally occurring osmotic pressure) on...
  4. AquaFX

    Reverse Osmosis & Deionization

    TDS Creep The permeate pump manufacturer claims the pump eliminates TDS creep; I have not personally verified it. It does stand to reason; the pump works by changing differential pressure across the membrane. I believe the feed water is feed in “spurts” so there is not a continues steam...
  5. AquaFX

    Reverse Osmosis & Deionization

    No Problem Cold Water is just going to slow the production rate down, the colder the slower Thats all, Marianne www.aquafx.net
  6. AquaFX

    Reverse Osmosis & Deionization

    Level controllers A top off system is commonly used, the best advice is to keep the unit from cycling alot. Meaning keep the time that the unit kicks on long as possible. Natural osmosis occurs when the unit is not under pressure and the will TDS will actually increase through the membrane...
  7. AquaFX

    Reverse Osmosis & Deionization

    Gpd That is true with most membranes. I believe everyone but DOW rates @ 60 PSI. DOW rates theirs @ 40PSI. TDS is around 120ppm, (again with DOW) Not sure with others. I do know that DOW is very conservative and you Normally get the projected flow rates. NOT A PLUG but you get what...
  8. AquaFX

    Reverse Osmosis & Deionization

    Feed Back Please! Let me know what else you would like, or I promise you, I will just keep ranting :lol: :shock: :doubt: :eek2: Marianne www.aquafx.net
  9. AquaFX

    Reverse Osmosis & Deionization

    Meters and Gauges This is a good next topic, because it ties in with the one before it. You NEED a pressure gauge, now the word need is subjective, but I believe you NEED to gauge the pressure of your system. First it lets you know your system pressure when all the prefilters are new...
  10. AquaFX

    Reverse Osmosis & Deionization

    3 things affecting efficiency of an RO Got crazy busy :oops: sorry it took me so long to get back The 3 things that will dictate how well your system operates are pressure. temperature and water quality. 1. Pressure; Most membranes can handle hundreds of pounds of pressure, and the more...
  11. AquaFX

    Reverse Osmosis & Deionization

    Scott, As soon as the water passes through the carbon, there is no more residual disinfection. This means there is a potential for undesirable baterial growth. Now the water is purified, and the membrane can deal with A LOT. Again the TFC membranes are bacteria resistant (just not chlorine...
  12. AquaFX

    Reverse Osmosis & Deionization

    You are correct:) TDS creep is natural. When you stop "reversing" osmosis (or applying pressure to the feed water side of the membrane) OSMOSIS happens. Even when you are applying pressure, osmosis is still present, the higher the TDS the higher natural osmonic pressure is. That is why you...
  13. AquaFX

    Reverse Osmosis & Deionization

    DI Resin Ken, You can use any type of filter that will provide the water full contact with the resin. For instance; in a tradtional filter housing the in and the out are at the top. This way all the water has to travel the entire length of the resin column to exit. If you like the idea...
  14. AquaFX

    Reverse Osmosis & Deionization

    The initial work we did here trying to get eliminate the chloramine would tell me it is possible, but extremely time consuming and expensive. We tried lowering the pH of the incoming water to more easily strip the chloramines, but once you take the water out of a pressure line (if you are going...
  15. AquaFX

    Reverse Osmosis & Deionization

    You are on track and that is somewhat true;) the trick is to learn all you can about membranes (oh yeah I forgot, some people actually have a life).:rolleyes: Instead the specs sheets on membranes need to be understood by the RO manufacturer. The spec sheets reflect a certain set of...
  16. AquaFX

    Reverse Osmosis & Deionization

    Membranes The most popular membrane material is Thin Film Composite (TFC). This material is NOT chlorine tolerant, but they can handle bacteria attack. There are Cellulose Triacetate (CTA) that are chlorine tolerant, but bacteria will destroy a CTA membrane. Also, CTA rejection rates are no...
  17. AquaFX

    Reverse Osmosis & Deionization

    The only time you will "need" 2 carbons is if they are "Chloramine Blaster" carbon. You need 2 to get enough contact time to take care of the ammonia in the chloramine. If you have chlorine only, one carbon (any type) will remove the chlorine. Using a 5 micron sediment filter before a 1...
  18. AquaFX

    Reverse Osmosis & Deionization

    Carbon The second stage is normally carbon. This is done (in Reverse Osmosis) to protect the membrane from chlorine. Chlorine will ruin a Thin Film Composite (TFC) membrane. TFC is the most common membrane used today (more on membranes later) Carbon's magic is it's incredible surface...
  19. AquaFX

    Reverse Osmosis & Deionization

    WorkShop I am not sure what the difference is, if I do this well, it should be all of the above. Marianne www.aquafx.net
  20. AquaFX

    Reverse Osmosis & Deionization

    GREAT! Sediment OK, sediment. Sediment filters remove/reduce what is referred to as "suspended Solids" ;think sand. It is physically filterable. Iron particles, Sand, Calcium that has scaled and then come lose, any fragments that do not dissolve will be in this category. These particles...
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