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Misconceptions regarding nutrient deficiencies, buffers and pH
- To: <Aquatic-Plants at actwin_com>
- Subject: Misconceptions regarding nutrient deficiencies, buffers and pH
- From: "James Purchase" <jpurch at interlog_com>
- Date: Mon, 4 Jan 1999 12:38:09 -0500
- Importance: Normal
- In-Reply-To: <199901040848.DAA20041 at acme_actwin.com>
Adam Weingarten recently posted the following:
> I have some severe nitrogen deficincies in my tank. I have used tetra
> Hilena Crypto, but since it contains phosphate the algae in my tank goes
> crazy. I have read that KNO3 seems to be the most efficent method to
> provide nitrogen. So my question is where can I find it? Is it sold
> under any other names?
The new label on Tetra Hilena Crypto, Tetra Initial Sticks, and Tetra Flora
Pride all contain a series of numbers, XX - YY - ZZ, where XX is the
percentage of N, YY is the percentage of P, and ZZ is the percentage of K.
If I'm not mistaken, Crypto Tablets list P as 2, which is not a terribly
large amount of Phosphate, especially as the tablets are meant to be
inserted deeply into the substrate. If you are having an algae problem, I
doubt that it is being caused by the amount of Phosphate in the Tetra
product, at least if you are using it as it was designed to be used and in
the quantity which is recommended.
Someone several years ago had an algae problem in a tank in which they had
used Tetra products and they attributed the outbreak to Tetra. This myth
seems to have been circulated widely and I believe it is a major reason that
Tetra now lists the N-P-K ratio on each of it's plant products.
> Another unrelated question that I have is pertaining to ph stuff. I
> recently got some discus and I had to lower the tank PH from 8 down to
> 6.5 - 7. I used Aquarium pharmacudicals proper ph. I had heard that this
> contains phosphate, can anyone confirm this?
I don't wish to be guilty of the same fear mongering which I described
concerning the Tetra products, but I suspect that Proper pH uses a Phosphate
or Bi-Phosphate buffer. Most commercially available buffers intended for
general fish tank use do contain Phosphate . Some, and they are usually
clearly labelled as such, are designed for use in plant tanks, and they use
a different chemistry to work their magic and are thus Phosphate free. This
should be clearly shown on the label (as an example - Seachem Acid Buffer is
phosphate/carbonate free while their Discus Buffer is not. The typical
discus breeder maintains their fish in bare tanks so some phosphate is not
going to bother them).
Adam also notes a side effect from his use of Proper pH -
> become extremely cloudy after using it. I tried diatoming it,thinking
> that it my green algae bloomhad been resurrected, but it was still
> cloudy. Normally the diatom filter did the trick. What's at work here?
> Why Is my mater cloudy?
If you check with Aquarium System's web site, you will see that the company
clearly states that the use of Proper pH can have the following effects...
"Hard alkaline water fights against PROPER pH and can cause a slight haze
that is not harmful and will be removed by aquarium filtration."
"When PROPER pH tablets are used in extremely soft water a slight foaming
may occur on the surface of the water due to low surface tension. This is
not harmful to fish or plants and will disappear in time."
"When using PROPER pH along with water clarifiers, a temporary cloud may
form. This is non-toxic to fish and will quickly be filtered out of the
So, depending upon what ELSE you are putting into your tank, you might see
one or more of the side effects noted above. You also don't say what the
Hardness and Alkalinity of your source water is so recommendations are kind
of hard to give with any accuracy.
> Finally, what are some other alternatives to get my water ph down from
> 9-10 range? I never had much luck with peat. Fooling around with 9M HCl
> hardly seems safe any where near or relating to a fishtank.Is there any
> way to reset the kh and gh?(If I boiled some of my tap I could probably
> drive nails wth the remaining mineral deposits) Would black water
> extract work? Are there any different ph target buffers that wouldn't
> produce the same cloudy effect?
Ouch! Is that pH from freshly drawn tap water or after it has been sitting
for a while? What are you using as a substrate in your tank? And what else
to you add to the water?
Peat is a no-brainer for softening water and helping bring down the pH into
more desirable levels. Get yourself a 67 L Rubbermaid plastic storage
container (under $10.00 in any hardware store) and put a few handfuls of
plain peat moss (containing no additives - the stuff designed for use in
gardens is perfect, and available at the same hardware store where you find
the storage container) into a fine mesh bag (an old nylon stocking works
perfectly) and let the peat soak in the water for a week or so, measuring
the Hardness and pH of the water every day until you achieve the parameters
you desire. If the brown tannins which will leach from the peat are
objectionable to you, you can filter them out using activated carbon before
you use the water in your aquarium.
In the same issue of the APD, Kudzu posed the following question:
> I have been reading with interest the RO water posts. I have been toying
> with buying an RO unit for some time now. The question I have is what to
> use as a buffering agent in regards to planted tanks. I seem to remember
> some talk about Proper pH causing algae growths?
The perfect buffering agent to increase the Alkalinity of R/O water is found
in every kitchen - Baking Soda. There is no need to spend any time searching
for something else better (and more expensive), as Sodium Bicarbonate works
As for the comment about Proper pH, see my comments above.
> If I wanted to set up a tank with a PH around 6-6.5 for the fish
> and it was
> to be planted (lots of lighting) what would be a good choice to use for
The misconception about HAVING to have maintain a pH of 6-6.5 continues to
amaze me. Fish and plants are wonderfully adaptable and there is really no
need to pull your hair out trying to maintain an artifically low pH, unless
you are attempting to breed certain sensitive fish species.
With R/O water, properly buffered using Baking Soda, the addition of Carbon
Dioxide will bring your pH into the range where the vast majority of plants
and fish can thrive.
Finally, a lot of people have recently posted concerning deficiencies which
they feel exist in their tanks and their attempts to recify those supposed
deficiencies using such things as 20-10-5 fertilizers.
Nutrient deficiencies can be extremely difficult to diagnose. Depending upon
the results of a hobbyist grade test kit to measure the amount of a nutrient
in the water is an "iffy" process at best and probably useless when trying
to determine a deficiency situation in an aquarium. You have to know what a
healthy plant LOOKS like and you have to see an OBSERVABLE difference which
can NOT be attributable to something else before you can even reasonably
assume that a problem MIGHT exist. The only sure way to diagnose some
deficiencies is thru tissue analysis, a process beyond most hobbyists. Just
because a hobbyist grade test kit is unable to show the presence of a
certain nutrient does not mean that this nutrient is in short supply and the
cause of a deficiency.
I have a tank which was set up and is being maintained using the soil
substrate method advocated by Steve Pushak. I have NEVER been able to
measure any Iron in the water column of this aquarium (using either a
LaMotte Iron Test Kit or a Seachem Iron Test Kit), yet I don't see any signs
of a problem which might indicate a lack of Iron. Micronized Iron was used
in the substrate of this tank and is obviously being made available to the
roots of the plants but it is not present in measurable amounts in the water
Following the logic which some people seem to be using, the failure of my
test kits to resolve Iron in the water would lead me to the assumption that
the tank was Iron limited, when in fact no problem exists. Similarly, I
suspect that in a heavily planted tank, any Nitrogen compounds are absorbed
by the plants long before they can register on a test kit, negating a common
assumption of Nitrogen limited plant tanks.
You really do have to learn to LOOK at your tanks over time to detect any
trends which might indicate problems. A quick check with a test kit is not
always the best diagnostic tool. There is just as much art involved here as
there is science.
From the frequency of such posts, I would venture to guess that not a lot of
people are taking full advantage of the archives of the APD. There is a
wealth of information available on nutrient deficiencies and how to
avoid/resolve them in the archives.