Re: Water quality message.

On Fri, 03 Jan 1997, Christian Cotichini wrote:

> When I first got the tank I tested the local water (I'm in
> Vancouver, BC) and found the following:
> pH = 6.0
> Hardness (ca, mg) = 0-10ppm (very soft)
> After discussing this with the aquarium store they said that
> I should raise my pH.  They gave me a 2 (1 lb.?) bags of
> dolomite (sp.?) and told me to add this to the gravel when I
> set up the  tank  They said nothing about the hardness.
> After setting up the tank and adding the fish and plants, I
> tested the water to be 7.4 pH.  This is way higher than my
> target pH (6.6-6.8).  Furthermore, when I do a partial water
> change  with 6.0 pH tap water, the tank shoots back up the
> 7.4 in a few hours.

I use R/O water with Kent R/O Right (ph around 6.6). Around 15 months 
ago, I redid my tank using some nice black gravel from my aquarium shop - 
in use in their tanks with no trouble. I found my water jumping to a pH 
of around 8 and hardness up around 12 dH. I tried massive dilution with 
more R/O water, anything I could think of, to no avail.

The shop eventually found out about 2 months later that the problem was 
something in the gravel. The first loads taken from the top of this 
gravel bed were fine, but as they got lower down removing it, something 
else was in the gravel and it increased hardness and pH. Other people had 
the same problem and no-one could fix it.

The upshot was they gave me new gravel (quite voluntarily - a good shop!) 
and I went through the pain of setting up the tank again. I think this 
will be your only solution - it would take years to dissolve out the 
dolomite and get rid of it by water changes. Total replacement is the 
only solution I managed to come across to a similar problem.

There are a number of good products for increasing hardness - Dupla have 
KH tablets and KH/GH tablets, Kent have pH Stable, Sera have a liquid 
KH+. No doubt there are others. All of these products come with dosing 
information to let you calculate how much you need to add to reach the 
level of hardness you want. I would recommend being very grateful for 
your soft water and using this sort of product. A little practice will 
get your dosing right. If you make a mistake and get things too high, 
just don't add any to the next water change and hardness will come down 
again, or just do a straight water change to bring it down. Raising 
hardness and pH is a much simpler task than reducing them, which is the 
problem I face in Brisbane, Qld Australia where tap water after treatment 
now is around a pH of 8 and quite hard.

David Aiken