Re: Water Softener question

["A. Inniss" <andrewi@u.washington.edu>]

On Wed, 30 Apr 1997, Ed Pon wrote:

> I am using a Culligan water softener which replaces calcium ions with sodium 
> ions to soften the water.  The tap water comes into the unit at about 120 ppm 
> carbonate hardness and leaves  the water softener at o ppm(using an Aquarium 
> Pharmaceuticals, Inc. Water Hardness test kit).  I quit using my reverse osmosis 
> unit because of the convenience factors.  I have had spawnings from A. 
> Pandurini, A. Nijsenni, A. Cacatoides, A. Borelli, A. Norberti, A. MacMasteri, 
> A. sp. Rotpunct, and probably a few others that I can't remember at the moment.
> My water source is not terribly hard to begin with, so I figured that I wasn't 
> really putting very much sodium into the water.  Also, cichlids in general, seem 
> to have a high tolerance for salt, with some species actually reproducing in 
> pure salt water.  Anyway--I have been not been able to get an answer to a 
> question that I have posed to various authoritative people in the cichlid hobby 
> in the past.  The question is: do soft-water fish in general, and cichlids in 
> particular, actually require a low carbonate hardness to reproduce successfully 
> or is the requirement for low conductivity.  I know that some people measure 
> carbonate hardnes, some measure total hardness, and others use a conductivity 
> meter to determine the suitability of their water for breeding soft-water fish. 
> Anybody out there have any opinions, facts, theories, etc?
>  
> 
	I'm not an expert on these issues, but here's an opinion, at
least: Any of the factors you mentioned (Na, KH, GH, Conductivity) can
have an effect on "successful breeding".  Any of these factors is going to
have an impact on osmotic pressures, and so may affect breeding behaviour
in the parents, and viability of the eggs and fry.  Now, I'm not going to
state categorically that "successful breeding" (viable, healthy, abundant,
sex-ratio balanced etc. fry; healthy, 'good', etc. parents) cannot occur
unless we mimic natural water conditions.  In fact, Loiselle and others
mention examples of fish having apparently 'better' broods in water very
unlike their natural habitat. However, I'm inclined to believe that
usually, fish breed most 'successfully' when we mimic as closely as
possible their native water conditions.  For fish that come from water
with low GH, KH, and Conductivity, I'm mildly skeptical that you'll have
'successful' breeding, especially if the fish in question are wild-caught.
(IMHO, captive bred species, especially if captive bred for a few
generations, tolerate not 'ideal' conditions better).  If the parents are
inclined to breed in such conditions, the eggs may have trouble hatching.
I think GH is most relevant to this last point, but others may disagree.
I'm really unqualified to say much about how Conductivity might affect the
eggs' hatching, but I will say that water that has been softened by a
system like you describe, will have the benefit of a low GH, but the
resulting sodium may complicate the fishes' osmoregulatory processes to
the point where they may not go through the mating ritual etc.  Then
again, you say you've bred A. nijsenni, which 'should' require very soft,
acidic, low conductivity water, so....   You've also bred A. pandurini,
which caught my eye: I managed to scoop a pair that were cantaminants in a
shipment of nijsseni, and I wonder whether you would be so good as to give
some breeding info.  The usual, such as water conditions, spawning
behviour etc.

		Hope some of my long-winded blather proves useful to you,

			Andrew