Re: water question

["Darren J. Hanson" <djhanson@calweb.com>]

At 04:08 PM 11/7/97, William M. Groth wrote:

>I have a water question myself regarding raising & spawning Apisto's.  We have
>a water softening unit which uses resins.  Thus the water is soft coming
>out of the tap and we have a carbon unit in the water softening system so
there is no
>chlorine and I am able to do water changes from the tap.  The water is now
>soft but it is still high in disolved solids so far as I know.  

>Could someone explain
>the exchange process used in water softening systems and tell me if this water
>will work for Apistos and other South Americans or do I need to go to RO
>water?

>Some help on the water chemistry and reactions of various dwarf species to
>those water conditions would be much appreciated.

Without going into a full scientific trestie, which is impossible without
knowing exactly which resins are used in your water softener and precisely
what is disolved in your source water at any given moment, here are my
impressions.

As your water softener is actually using cation and anion exchange resins to
soften the water, I would expect it to be pulling down total alkalinity (AKA
carbonate hardness) which is what buffers your water to a specific pH. Now,
the soft water that most apistos come from is quite high in TDS and disolved
organics as the acidity is coming from rotting vegitation. What I would
check is what the pH of your tap water is along with its total alkalinity.
If total alkalinity is very low, it can be hard to maintain a stable pH. And
even with a moderate total alkalinity, it will still be possible for your
fish tank to slowly drift to a significantly lower or higher pH. Check your
water at least weekly for a couple of months and you should be able to
figure out how often you need to do water changes to keep a stable water
chemistry.

Now if for some reason your total alkalinity at the tap is still very high,
then you may need to consider an RO unit to bring alkalinity down to the
point where you can effectively adjust pH at all.

Just my 2c worth. Your milage may vary.

- -- dj