DI filter from LFS

Discussion in 'Water Chemistry' started by new2salt2, Feb 19, 2004.

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  1. new2salt2

    new2salt2 Fire Shrimp

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    ok.. i know what you are all going to say, but hear me out.  I was in the LFS and talked about a water filter for my reef tank.. they owner told me that he does not use a RO filter just a DI tap water filter.  this is the unit with a screw on filter with lids and a small spring.  he said that if i dont have a reef completely full of coral i shoudl be good using this only.  I looked and sure enough they are only using the DI filter AND HE SOLD RO too and that is why i was not suspicious with his sales pitch.  

    all i have right now is a few star pollups and was wondering if you all can give me some tips.  is this a sufficiant filter for a small amount of coral?  until now i was not using anything at all.

    this is a 50 gal tank with at least 60 pounds of live rock and about 10 star pollups
     
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  3. Land_Fish

    Land_Fish Guest

    What was his reason he did not use RO water?
    DI filters filter things out that the RO membrane can not filter and vise a versa.
    Depending on your water quality will determine when you need to change the DI filter that he is suggesting. I have used these before and they are ok but they are used up very fast. I do believe they can only handle 60 gallons of water before you need to change them. At a cost of 25 bucks for one refill you will be spending more money in the long run compared to a 5 stage RO/DI system that costs around 149 which has pre filters and a RO membrane before the water even gets to the DI filter which will extend the life of the DI 4 times longer than the single DI filter you mentioned.
    When you get a gallon of water from the LFS have him do a TDS meter reading to see how pure this water is.
    Water coming from a RO/DI system will read 0 with a TDS.
    I would think the reading on the DI when brand new would still read in the 20 ppm TDS meter test. Pure water is from 0 to 5 ppm which when combined (ro/di) is the best thing for a reef aquarium.
     
  4. new2salt2

    new2salt2 Fire Shrimp

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    he said that it was not needed unless i have a bunch of coral and that he has never used one ever and has no problems with his display tank.
     
  5. Land_Fish

    Land_Fish Guest

    RO rejection rates
    [table][tr][td]The reverse osmosis process utilizes a semi-permeable membrane to remove and reject a wide variety of impurities.  
    Aluminum 97-98% Nickel 97-99%
    Ammonium 85-95% Nitrate 93-96%
    Arsenic 94-96% Phosphate 99+%
    Bacteria 99+% Polyphosphate 98-99%
    Bicarbonate 95-96% Potassium 92%
    Bromide 93-96% Pyrogen 99+%
    Cadmium 96-98% Radioactivity 95-98%
    Calcium 96-98% Radium 97%
    Chloride 94-95% Selenium 97%
    Chromate 90-98% Silica 85-90%
    Chromium 96-98% Silicate 95-97%
    Copper 97-99% Silver 95-97%
    Cyanide 90-95% Sodium 92-98%
    Ferrocyanide 98-99% Sulphate 99+%
    Flouride 94-96% Sulphite 96-98%
    Iron 98-99% Zinc 98-99%
    Lead 96-98% * Virus 99+%
    Magnesium 96-98% * Insecticides 97%
    Maganese 96-98% * Detergents 97%
    Mercury 96-98% * Herbicides 97%
    % TDS 95-99%  

    * These are conservative estimates [/td][/tr][/table]
     
  6. Land_Fish

    Land_Fish Guest

    I look at it this way: My corals and fish when adding the cost of these deserve the best care I can provide them. Why gamble losing any of my live stock that I have raised and cultured when I can provide a better environment for them with RO and DI water. Why take that risk?
    As I said above both RO and DI together make for the perfect water solution for fish and corals.
     
  7. new2salt2

    new2salt2 Fire Shrimp

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    k thanks.. BTW you got a list of what a DI only filter would remove? just to compare?
     
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  9. Land_Fish

    Land_Fish Guest

    The DI cartridge contains ion exchange resins which remove the last traces of contaminants from the RO product water.
    DI System provides the removal of silica, colloidal silica, phosphates, nitrates, and heavy metals.

    I think it is really a big secret when coming to the % of rejection rates on the DI Because I have looked for some time now and still can't find the %'s of rejection.

    I really don't think you can have a set % with the DI filters as it absorbs the impurities and depending on the water used will determine the actual rejection / absorption rate. Means the purer the water going the better the water going out. This is why it is the last filter on the RO/DI system.