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Re: Can KMnO4 & iron rust act as PMDD?
Chee Ming asked:
"I've thought about mixing my own
fertilizer but my chemistry knowledge is so very limited and so is my
knowledge about plant requirements."
You can find most of what you need to know about plant requirements from the
Internet, there is a great deal of information online today. Places like the
KRIB [http://www.thekrib.com/Plants/] are a great place to start, and Steve
Pushak's web site [http://home.infinet.net/teban/] has a great deal of
information and links to sites on plant nutrition. Spend some time reading.
When dealing with sometimes exotic chemicals and living things, a little
knowledge can be a dangerous thing. Do you keep fish in your aquariums with
your plants? If you don't know the first thing about chemistry, or if your
chemistry knowledge is limited, you could be endangering the health of your
fish, not to mention your own health, but using chemicals which may or may
not be safe.
For example, many times people post to the APD wondering about the use of
this fertilizer or that fertilizer that they may have laying around in their
garden shed - usually they are trying to save some money. One very common
scenario revolves around the use of urea based fertilizers - they use it and
wonder why their fish die. Without knowing that a lot of fertilizers
designed for land plants are at least in part urea based (which means you
are adding ammonia to the water in your aquarium and this can hurt or kill
your fish) they go merrily on their way and then come running to the list
wondering what went wrong (usually after they have killed all of their
fish). Oh well, chalk one up to experience......won't do that again, will
we? [if you doubt this, do a search on the APD archives using "urea" as a
Not to coin a phrase, but it isn't rocket science..... you _can_ do it, if
you really _need_ or _want_ to do it. But it is incumbent upon you do learn
what effect any particular chemical or mixture of chemicals might be before
you add it to your aquarium. The PMDD "recipe" was worked out by people who
knew what they were doing and who had a good grasp of chemistry. The papers
outlining their research and the follow-up comments and discussions are
archived on the KRIB
[http://www.thekrib.com/Plants/Fertilizer/sears-conlin.html] and should be
read a couple of times by anyone contemplating a do it yourself approach.
The chemicals are all available commercially from a number of sources - and
if at all possible you should probably not substitute other chemicals for
the ones listed unless you find out in advance that they will work and are
safe, both for you and for your fish. Saving a few bucks by using something
you find in a box in the garage rather than mail-ordering the proper
chemical from a hydoponics store could seem like false economy if you end up
killing a tank full of adult Discus.
Going the do it yourself route because there is "a lot of talk about it" is
probably not wise until you have done some research and understand the why's
and how's of the approach. And understand that you can do more damage than
good if you put the wrong chemical into your tank.
There are many companies which have high quality, proven products
specifically designed for aquatic plants in aquariums. Properly used, they
will safely meet the nutritional needs of 99.99% of the plants we commonly
grow in aquariums, and they will do so without affecting your health or the
health of your fish. Most of the better manufacturers have taken the time
and done the proper research to ensure that their products are nutritionally
complete, when used as directed. Dupla, Seachem, Aqualine Buschke, and ADA
are just a few of the many companies that sell complete and balanced lines
of plant care products which might save you grief.
If you follow the APD with any regularity, you will notice that people like
Thomas Barr and Roger Miller are always stressing the importance of
"balance" - in order for plants to do well, all of their growth requirements
must be present in the proper balance - neither too much nor too little of
any one thing. This is a very important concept to understand. You can't use
a shotgun approach when maintaining an aquarium, you have to make sure that
everything the plants need is present, and present in a dynamic balance with
all of the other factors plants require. You want to add KMnO4 to add
Potassium and Magnesium as "trace elements". Potassium is not a trace
element - plants use quite a bit of it, but they can only use it when all of
the other macro and micro nutrients are also present in the correct ratios
(or range of ratios, as these things can vary over a wide range).
The nutrients must also be present in a form that it useable by the plants.
Your query about "iron rust" indicates that you might not be aware that rust
is iron oxide which isn't directly useable by plants as a source of iron.
Organic acids and bacteria can, over time, convert some of the iron into a
form useable by the plants but only under certain conditions and a much
easier and more direct route would be to use something like Flourish Iron.
[Having re-read that previous paragraph, I just _know_ that there is at
least one person who is going to say that he puts steel wool into his
substrate (under a layer of cow manure no less) as an iron source......and
yes Richard, I know that you claim it works for you......hehehehe.]
I'm not trying to disuade you or anyone else from using a do it yourself
approach - many people, myself included, have used it with great success.
But do spend some time reading over the reference material that is available
online first and understand why you are doing it. Since you are in
Singapore, try to get in touch with some other local hobbyists - there are
lots of folks there who are quite helpful and knowledgeable.