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Re: KATI / ANI vs. RO / DI

Andrew writes:

> Hello all,
>       
>       I just got off the phone with a tech rep at Pet Warehouse.  I wanted 
to 
> 
>  know
>  if the ANI (anion removing DI filter) could be used by itself to remove 
PO4 
>  from
>  my tap water.  He didn't really have an answer, but recommended that the 
ANI 
>  be used with the Kati, (the cation - removing unit, designed to be used 
> together to produce pure water) which will cost me ~ $229.(Both units)

The PO4 ions, while floating around in the water free of any attachments, is 
still associated with some cation of some sort, be it Ca, Mg, Fe, whatever.  
The PO4 ions will be replaced by the ANI unit with OH- ions.  Then suddenly 
you have all these hydroxides floating around, and your pH will go way up, as 
your water becomes more base.  The KATI unit will replace the cations with H+ 
ions, the majority of which will then "hunt down" the majority of the OH- 
ions, and form water molecules, thereby neutralizing the cations and anions 
completely.  Doing one side without the other established an extremely acid 
or base water, which is not what you want.

> I can get a Kent Marine RO/DI Maxxima unit for the same price, but I'm not 
sure if > Kent resins can be recharged?

Don't know either.

>       The Kati/Ani solution has a few advantages:
>  
>  1.  Both can be recharged with HCl (Kati) and Sodium Hydroxide (Ani)
>  (And yes they are nasty, caustic compounds, but wearing goggles, gloves, 
and 
>  an apron should do the trick)  The Kati 2 (the larger size) is rated at 
around 
>  2000 gallons between recharges, which will last me ~ 2 years before I need 
> to reach for the acid.  The Ani 2 is similar.  
>  
>  2.  Can produce up to 360 gallons per day. (The Kent RO unit mentioned 
above   >can only produce 50 gallons per day)
>  
>  3.  No Wastewater!!  The RO units dump 4 - 6 gallons of wastewater for 
every 
>  1 gallon of pure water produced.  What a waste.  I don't live in a water - 
>  restricted area like certain areas of CA, but why waste water if you can 
help it?
>  (I suppose I could always save the water and use it in the garden)

Thank you.  Someone thinking globally.

>  
>  Disadvantages:
>       I'm not aware of any, perhaps someone out there is?
>  The only possible disadvantage I can think of is:  After the unit is 
>  recharged, the first 12 gallons of water are thrown out. (I'm guessing 
this 
>  is to wash out any residual amounts of caustic soda or HCl left over from 
> the recharge procedure).

A reasonable sacrifice when compared to RO.
     
>       I would like to use the Ani unit alone, to remove PO4, but even 
though 
>  he(the tech rep) didn't recommend doing this he couldn't give me a 
specific 
>  reason either.

See above.
  
>  I do know that Kent Marine does not recommend using their DI anion - 
> removing resins alone, because the life of the resin is reduced.  Why this 
is so has 
>  never been explained to me.  Any ideas?  
> 
They mean as opposed to using the RO unit in front of it.  The RO unit 
removes the same types of ions as the KATI-ANI De-ionizer, so there are very 
few ions to use up the resins.

Bob DIxon