Xref: 127.0.0.1 rec.aquaria.freshwater.plants:76768


"Greg G." wrote in message
...
On Sat, 8 Nov 2003 16:18:23 -0500, "NetMax"
wrote:

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Now, a year later, the water coming from the tap has a pH of 8.3!
Even though the hardeness levels have remained the same.
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What on earth are they adding to the water that is causing this?
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Caustic soda is what my municipality adds to bump the pH up.

NetMax

Thanks, I had about given up on an answer-short of taking it to a lab.

Any ideas on counteracting this, short of R/O-DI or peat filtering?

Greg

The first step IMO would be to ascertain exactly what your municipality
is doing. Contact them and they will FAX you the water parameters and
some history. The addition of caustic soda is to reduce the decay of
their pipes. It might be transitional while maintenance or
infrastructure work is underway, or they might be about to change to a
different method. Make your plans from accurate information.

AFAIK, caustic soda has no effect on gH or kH, only pH, and it's not
particularly stable. In my situation (7.6pH, 2-3dgH, 1-2dkH), it's easy
to drop the pH with CO2 injection as the kH is so low, however there is
some danger of a pH crash (even without CO2). Our municipality's water
leaves the treatment plant at 9.1pH, but 7.6-7.7pH is what I typically
get out of the tap. Time of day, and day of week may also influence your
pH. Standing water pH will be much lower, so Sunday night's water
should be much more acidic than Monday afternoon.

I've just started to add a bag of crushed coral to a filter compartment
to see if I can boost the kH slightly while keeping the pH in the low 7s/
high 6s. It's an experiment to see if I can achieve some greater
stability through non-chemical means. My test application is a high
fish-load, 1/3 planted, non-CO2 tank running 50% w/c per week (almost
continuous w/c system). If anyone has any other ideas on how to
counteract caustic soda without stripping my last few remaining
carbonates, I'm all ears.

NetMax