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SubscribeIdeal way to lower the pH
Mega Fish
Posts: 1037
Kudos: 96
Votes: 0
Registered: 30-Sep-2002
female usa
Hello everyone. For my fish tanks, I use my tap water, which comes from a well but is pretty basic, around 8.0. The tap water does not go through a water softener. The KH of my tap is 3 degrees, and my GH is 6 degrees.

In the southeast Asian backwater setup that I am planning, I wanted to keep dwarf gouramis, pygmy rasboras, and kuhli loaches; however, I am conscious that these species prefer a mildly acidic to neutral environment. I was hoping to lower my pH to accommodate these species, and I was experimenting with several different ways to do this, primarily mixing tap water with distilled water and filtering through peat.

When I mixed half tap water with half distilled water, I got a pH of 7.5, a KH of 2.5 degrees, and a GH of 3.5 degrees. When I filtered tap water through peat, I got a pH of 7.5, a KH of 2 degrees, and a GH of 4 degrees. When I mixed half distilled water AND half tap water filtered through peat, I got a pH of 7.3, a KH of 1 degere, and a GH of 2 degrees.

Even though the last option got me the lowest pH, I feel uncomfortable with how low the KH is, because I don't want any risky swings of pH in my tank because of the low buffering capacity (particularly because this is a ten gallon tank). I'm a little confused about why I still have a pH that is not very acidic (and even above neutral) when I have such lower water hardness!

The other option I had was to use DIY CO2, because the tank will be heavily planted and judging from my pH and KH, I have pretty low CO2 levels currently. And I know that this would lower my pH.

So I would like to hear some opinions on this, because I'm not sure what the best option is for lowering my pH. If I used peat in my filter, would the pH be increasingly lowered if I used a greater amount of peat? Or is there a "plateau" that takes place? What is the ideal amount of peat to use per gallon?

Another issue is that if I used peat and the pH was around 7.5, I would be replacing the water during water changes with plain tap water, which is a pH of 8.0; is replacing 20% of that water with the more basic pH enough of a pH swing to cause the fish stress? If so, I could prefilter my water through peat for a day, it's just a bit of a hassle.

Sorry for all the questions! Hope everything makes sense. Thanks for any help!
Post InfoPosted 21-Aug-2010 04:27Profile AIM MSN PM Edit Report 
Posts: 5108
Kudos: 5263
Votes: 1690
Registered: 28-Dec-2002
male usa us-colorado
A supposition...
Because of your "mega fish" status, 6+ years on this
site, and the high number of "Kudos" in your information,
you have "been around" for a while and possibly have other
tanks at home. With that said you can do a blend of several
things, all of which could make that 10G tank a
real "project."

I would stick with the half and half idea using either RO
or distilled water. Purchasing Distilled Water can be a
real expense whereas purchasing a RO system would help all
of your tanks and so that expense could be spread across
them for justification. You could make another 10G tank
a "sump" for the show tank and use it for your "water
treatment plant" filling it with peat moss etc.

Generally speaking your Asian tank should have a pH between
6.6 and 6.8. However, the plants that you mention in the
Planted Aquaria forum and the fish you mention for this
tank will live healthy lives in the water that you have,
after treatment.
You are right about the KH reading. It should generally
be around a 3 for best buffering capability.
However, you can raise the KH and not the GH by the
addition of regular Arm&Hammer Baking Soda. A possible

Anytime "we" use carbonate substrates to keep the pH
high for African Rift tanks, or something such as RO
or Distilled water to keep the pH low, water changes
can make temporary differences.
That is why small, regular, changes are recommended
instead of larger water changes. pH swings do occur,
however you can keep them to a minimum by watching
the size and frequencies of the changes. By not "pushing"
the capacity of the tank with quantities of fish and
waste load, you can keep to smaller water changes. By
having larger quantities of plants vs fish, you also
improve the water quality and reduce the need for larger
water changes.

DIY CO2 is a whole 'nother beast! First, you cannot
"store" the CO2 produced. When you start up a CO2
generator, it puts out a very large amount of CO2 and that
tapers off as the yeast slows down and the alcohol level
builds up. Then you have to set up a second generator,
while you clean up the first, etc. The CO2 levels sky
rocket (especially in a small tank) and then plummet
and then take off again with the insertion of the new
generator. The CO2 levels vary like a sine wave and
over all do more harm than good. I would not advise
using a CO2 system in that small a tank. Rather, I would
use something similar to the SeaChem plant products
(liquid ferts) instead. I realize you were thinking of
the CO2 to lower the pH, but I don't think I'd mess with
it and instead manage it with your use of Distilled or
RO water.

Just some thoughts...

-->>> The Confidence of Amateurs, is the Envy of Professionals <<<--
Post InfoPosted 21-Aug-2010 12:17Profile PM Edit Delete Report 
Mega Fish
Posts: 1037
Kudos: 96
Votes: 0
Registered: 30-Sep-2002
female usa
I was wondering if someone would mention my number of posts. I have been out of the fishkeeping 'field' for about five years and I feel very out of shape, so to speak. I recently decided to rekindle the passion because I used to get so excited about it (when I kept more and bigger tanks). I have forgotten a lot, but I'm reviewing all my old literature. I'm actually a little embarrassed, to be honest, because I feel like the questions I'm asking are fairly basic, but I feel so unconfident about my memory and my judgment that it helps to bounce ideas off a person who is more expert than me.

Currently, this ten gallon is my only aquarium project. I wish I had the resources to set up my bigger aquariums, but it's not written in the stars right now in terms of my living situation. I actually had an RO filtration system established in my last house, but couldn't take it with me when we moved. Especially considering there's a chance that I might have to move again within the year, it doesn't make sense at those point to try to purchase another system.

Good point about the baking soda. I will look into that. I'm still a little surprised about why I have such low GH and KH while I have such a high pH, as I was given to understand that those values were correlated.

Is the reason you thought that distilled/RO water might be more appropriate for my setup than peat because of the slight swings in pH that would occur during water changes if I was using peat filtration (and not pre-filtering the water)? That makes sense, I just wanted to clarify. To be honest, I kind of enjoy the slight tint peat give off! But distilled water may be more appropriate.

Ahhh... I never thought about the sine wave of CO2 distribution, but that makes perfect sense. Good point. I used to use DIY CO2 in my planted 59 gallon tank. I was browsing in my LFS recently and saw a CO2 generator such as the Turbo CO2 Bio-System ( I've never seen them before, and did not realize they were so cheap! Just out of curiosity, do they develop CO2 at a more even rate than DIY?

Thanks for all your advice! It's been ENORMOUSLY helpful.
Post InfoPosted 21-Aug-2010 18:20Profile AIM MSN PM Edit Delete Report 
Posts: 5108
Kudos: 5263
Votes: 1690
Registered: 28-Dec-2002
male usa us-colorado
Welcome back to the hobby! You seem to be starting
back cautiously rather than jumping back in with a
"huge tank" and trying to pickup where you left off.

With the housing situation in flux that is probably the best
way to go. I followed your link for the CO2 generator and
to me, it seems to be just a "glorified" version of the
standard DIY CO2 generator that uses brewers yeast and
sugar in a two liter soda pop bottle.

You may want to hold off on the use of CO2 gas until you
get to tanks over 35-40G and then invest in a regular
bottled gas system. I use a 5 pound CO2 tank and it runs
at 2 bubbles per second (bps) 24/7. It takes about
5-6 months to exhaust the tank and then I swap tanks and
have the empty one refiled for $9. Once you purchase
the parts (regulator, one way valve, bubble counter, and
reactor) then your only expense is to replenish the CO2.

In small tanks, it is more economical to use the liquid
fertilizers such as the "Flourish" series. And for
heavy root feeders such as the Amazon Swords, use some
plant tablets pushed into the gravel around the plants'

The only caution is that the plants known as "vals" seem
to be sensitive to the "Flourish Excel" and there have been
accounts of whole sections of the plants dying off after
that products use.

My "problem" with the peat is only that I believe it
"exhausts itself" after prolonged submersion and if you
have it buried under a layer of substrate, then it means
a whole "do over" to replace it. My suggestion of a second
tank feeding your show tank was to use the second tank as
the "box" to hold the mass of peat moss necessary to make
the change in the water that you were looking for.

Any substrate is good, sand just presents some problems
and all of them revolve around the grain size. A thin
layer of sand will not "hold down" most plants and they
will pull up and float as their mass increases with growth.

The individual grains can find their way up into the
filtration system with just a small amount of agitation
where they can grind up the impeller in the pump and so,
prefiltration is necessary to protect the filter pump.

The spaces between the grains are extremely tiny thus
limiting the circulation through the bed. Because of the
small spaces they are easily clogged with bacteria and
detritus turning the bed into a huge anaerobic area that
turns black, becomes toxic, and gives off Hydrogen Sulfide
a toxic gas that smells like rotten eggs.

Flourite is an excellent substrate and it is now available
in several natural occurring shades that make the tank bottom
seem much more real. There are other so called plant
friendly substrates available. Most give off nutrients for
the plants to grow but those also "wear out" over time and
soon become inert and need to be replaced. Folks who
only want to set up a tank take photographs of that
project, and then tear the tank down and begin another one,
use that type of "soil." Its designed to "provide everything,
all at once, fast, and then peter out over a 1 year period.

Hope this helps...

-->>> The Confidence of Amateurs, is the Envy of Professionals <<<--
Post InfoPosted 25-Aug-2010 14:48Profile PM Edit Delete Report 
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