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I did a ph test for both the tank and the tap last week and the tap ph seemed strange. Last week it was ~ 8.0, a little higher than I remembered, where my tank runs around 6.0. I hadn't tested my gh or kh in over 2 years so I picked up a new kit over the weekend. I remember they were on the very low side, but couldn't remember how low. I got 1º for both of them. I retested the ph on the tap water again and got 8.4 . Thinking it was really strange, I tested it again and got a totally different reading. For some reason, I realised that the water temp was different the second time and I got thinking about someone that said they age their water because they don't like using water out of the hot water tank because it killed fish. Sooo, I got the water hot and tested it, got the water as cold as I could and tested it and then made it as close to the tank temp as I could and tested it. My results are below.

~100ºF 8.3
~45ºF 6.4
~78ºF 7.8 (approximate temp of the tank)

Of course I add the water out of the tap as close to the temp of the tank as I can get it so it wouldn't be either of extreme ph readings. (but its still higher than the tanks reading)
Can anyone make sense of this, and if they can, explain it to me? I know my water has almost no hardness, so that explains the ph in the tank, but the fluctuations with temp doesn't.

---

I used to be Snow White, but I drifted.
~ Mae West

Hi,
pH is the concentration of Hydrogen Ions (+). As the pH
moves toward the acidic (6's) there are more ions, and as
it moves toward the basic (8's) there are fewer.
The amount of ions is also temperature dependent as the
ions are formed from the organic reactions within the water
and an increase of temperature causes an increase in the
breakdown of the compounds.

All pH monitors contain temperature compensating circuitry
for stable, accurate, readings. What you are seeing is
completely normal and while the readings will vary with
temperature, your concern for the fish would be within a
restricted range of temperatures (74-78 +/- a couple).

Because your water is, from your comments, "very soft" it
contains very little Carbonate and the KH would be low.
The Carbonate in the water is what buffers the pH. In your
water a small amount of acid would create a large swing in
pH. That is the reason why your tap water has a pH of 8
while your tank water has a pH of 6. There is little or
no Carbonate in the water to buffer the acidic reactions.

Now, what you need to look at, because of the low buffering
capability of your water, is the gravel, water changes, and
your bioload. As the fish eliminate waste, and any left
over foods decay, and any dead plant leaves accumulate,
will produce organic acids as they break down. This
acid will cause your pH to continue to drop becomming
more and more acidic. This situation requires that you
are vigiliant in your water changes, and that you clean
the gravel with each water change. You will have to do that
just to maintain a resonable nitrate reading and good
quality water conditions for your fish.

Increasing your KH will add more buffering capability to
the water, and ease the situation, but is not a cure all
for the aquarium maintenance, it just won't be as critical.

Measuring an established tank for Ammonia and nitrite are
not necessary. However, one should regularly test the pH,
and KH and GH.
Unless you are using a well for your water, you
should recognize that cities and towns use different water
sources for their water and regularly change these sources
to give them a "break." Many towns will have wells in
different aquafers and rotate them to prevent one from
running dry. Others use a combination of wells and also
draw from nearby streams, rivers, or lakes. These flowing
sources are subject to changes by climate. In drought times
towns will draw from deeper levels of the lakes or may
build additional piping to draw from further out into the
source to get away from polution. All of these changes
occur without notice to the consumer and the water
companies will add chemicals, or change treatment processes
so that the water they put out to the consumer is safe
and relatively stable. Depending upon how sophisticated
The treatment plant is, they may start up a well ahead of
time and run the output from the well into a stream, ahead
of time before pumping it into the town supply. Doing this
eliminates the "stagnate" water that has been standing in
the well and the immediate aqufer. Others, simply switch
and process the new water. This latter method will give
the consumer water with more chemicals, a stronger taste,
and/or an odd smell for a few days until the well settles
down.

If you are using well water, realize the climate can and
will influence the water as it flows through the aquafer.
In drought conditions, the flow is slow, and it will
concentrate the minerals from the rock it flows through.


I hope all this helps...
Frank


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

Thanks Frank, that does help. I do know that the water only comes from one source, a pond in the woods outside of town. I can think of one instance a couple of years ago when it ran dry in the middle of winter because of a major water line break. We had to pump out of another pond and ended up with totally untreated water (and a boil water order) for about 2 weeks while it refilled.

I normally keep soft water fish (angels, cories, gouramis, bettas etc) so the low PH,GH & KH have never really been too much of a concern. I just won some Lake Victoria cichlids on Aquabid and now I'm wondering if I should buffer the water (adding crushed coral or something similar...no chemicals) to bring those perameters up a little. I really hate to mess around with it, but I'm guessing that these fish are only 2nd or 3rd generation, and going to be a little more fussy about my conditions. Any thoughts?

---

I used to be Snow White, but I drifted.
~ Mae West

Hi,
Yes, with any of the African fish that enjoy water that
is harder, I would use crushed dolomite, crushed limestone,
crushed oyster shells, or crushed coral, in that order as
a substrate, and include limestone rocks for caves/dens,
etc. (Hows that for a run on sentence!

Crushed dolomite or limestone are better than crushed coral
because crushed coral is mainly all CaCO3
(Calcium Carbonate) and does not generally contain
other minerals that the fish and plants would need such
as Mg etc.
One neat "trick" is to go to the local Feed-n-Seed and
get a bag of crushed oyster shells. Compared to
aquarium gravel they are "dirt cheap" and they come in
25 pound and larger bags.
One feeds it to fowl as grist for their gizzard. It is
a rich carbonate and when blended in with one of the other
substrates adds "a touch of class" to it with the
difference in texture. Placed by the handful at the base
of rocks, it looks like rubble from a reef.

Over time it will hold your water to a pH in the low 8s,
and as long as you do 10% water changes the pH won't vary
hardly at all. When you do a 40% or more water change, it
will take a few days for the pH to work its way back up
to where it should be.

Frank


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

Buffering water is easy provided you don't really care how high the ph goes. Water likes to stay at a high ph. It's lowering the ph that causes headache. For a cichlid tank just add some limestone and use a substrate that buffers like argonite sand, crushed coral, etc... The finer the grain the faster it will dissolve and the better it will buffer. The ph will sit right around 7.8-8.2 depending what all you use and it won't budge. Such things will run out eventually though and you have to top off argonite sand every few years because the sandbed will get shallower over time. Test the ph and kh occasionally and watch the substrate levels to make sure you replace it in time but if you use a buffering substrate for the whole tank it will take years to run out.

Thanks for the help! I'm going shopping tomorrow and am going to see what I can dig up. Feed supply stores are few and far between around here (not much livestock) , but I know where there is is a Tractor Supply that may have some crushed oyster shells.

---

I used to be Snow White, but I drifted.
~ Mae West

Hi,
Good luck on your quest.
When you get them be sure to wash them as if it were
regular aquarium gravel to get rid of the dust/dirt
and any other stuff.

Frank


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

Shopping was a success. I got a 25 pound bag of Dolomite and a very small bag of crushed oyster shells. I have to laugh though, the LFS that I go to (actually a very small chain of 4 stores) goes to the extreme with their questions. I had to tell the sales girl that I did know what I was buying, no I knew it wasn't just pretty white rocks, I did know that it was going to raise the water perameters AND she wanted to know what kind of fish it was for. The limestone rock caves are going to have to wait though, I have a real hard time spending good money on rocks.

---

I used to be Snow White, but I drifted.
~ Mae West

Hi,
Well personally, I think you may have found a good LFS!
Pointed questions and good answers. She would seem to
know what she is doing.

Have fun!
Frank


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