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My 20 gallon has been around 7.5 since I had it. Today I checked it and it was at 6 - 6.4. My 55 gallon tank is full of the same water ( from the tap ) and it has a ph of around 8. No both tanks are stup differently. My 20 gallon has a gravle substrate with some of the brown slate like rocks in it and my 55 has a sand substrate with some retaining wall bricks ( I did bake these before I put them in my tank ). They each also has some different plants. My 20 has some swords from Wal-mart that you buy as bulbs and my 55 has some moss balls and I just put some anubias nana in it. Also my 20 is stocked with fish and my 55 just has a few stow away MTS in it.

Could any of these differences cause a change in my ph.
The only thing that I can think of is the different kind of rocks.

thanks highjinx

Hi,
There are several possibilities:

First, is age. Have both of the tanks been set up for the
same amount of time with the same stocking levels? As tanks
age, they tend to become more acidic from the organic
compounds within the water. Declining pH is a symptom of
Old Tank Syndrome (OTS) http://www.bestfish.com/oldtank.html

What are you using for substrate?
Some, such as crushed coral, crushed dolomite, crushed
limestone, or crushed oyster shells with drive the pH
into the 8's and increase the GH of the tank. Others,
such as sand, and regular aquarium gravel are primarly
SiO2 and are inert.

What really are the rocks in the tanks?
Rocks can definately affect the pH and GH of a tank.
Those that do are called Carbonates, and generally
speaking will fiz when a freshly scraped surface has a
couple of drops of household vinegar dripped on them.

You mentioned a "brown" slate. While slate does indeed
come in a small variety of colors, for the most part,
it is the color that gives it it's name - a slate grey
to black color. It is a metamorphic rock. It used to
be a very fine sandstone or siltstone that was crushed
under thousands and thousands of tons of pressure and
baked in hundreds of degrees temperature for millions
of years. That pretty much eliminates the possibility
of carbonates and chances are if it really is slate,
it won't affect your water at all.

In some sandstones the grains of sand are "glued" together
by carbonate deposits, and these will affect the pH and GH.
They come in various shades of brown, pinks, and other
colors and some varieties do resemble the cleavage of slate.

I'm not sure what you are calling "retaining wall" bricks.
If these are busted up cinder blocks, they are made of
concrete, colored red, and can be leaching lime and other
minerals into the water. That would also affect the pH and
GH of the tank.

While this does not specifically say "This" is the problem,
it does give you some things to look into and think about.

Hope it helps...

Frank


-->>> The Confidence of Amateurs, is the Envy of Professionals <<<--

Frank,
Where do you get your information? I have been searching for ways to naturaly change water conditions.

Any sites that could explain ways to affect ph, ammonia, alkalinity, etc. would be very useful.

Thank You
highjinx

Hi,
I've been in the hobby for over 50 years, and as a
Geologist, I have the background for much of what I
mentioned.
It will take some time to piece the various pieces of
information together.

Here is one article:
http://www.thekrib.com/Plants/CO2/khgh.html

Another: http://www.thetropicaltank.co.uk/hardness.htm

As I find them, I will post them here.

Frank


Last edited by FRANK at 03-Apr-2005 00:31

-->>> The Confidence of Amateurs, is the Envy of Professionals <<<--