Paul Sears wrote:
> I am now of the opinion that if there is little nitrate in the
>water supply and no major source of potassium in the substrate, most tanks
>short of potassium. This then means that the plants cannot use the
>nitrogen, and nitrate builds up. I think that a lot more tanks would be
>"nitrogen limited" if potassium were supplied adequately.
Another point in favor of Mastregrow for those who don't want to fine tune
their own formula.
Mastergrow contains relatively large amounts of K and Mg as well as much
smaller amounts of trace elements.
Paul also wrote:
>> I'm not disagreeing with your
>> approach, or your advice. But I also know how many beginner aquatic
>> gardeners _start_ with high nitrate levels.
> If they have no nitrate in their tap water, they are short
>of K, trace elements or both.
Not if they are even shorter on light, which is very often the case.
> I wish people would _read_ what we
>wrote rather than using another fertilizer recipe blindly. Only
>add the nitrate if you can drive the tank nitrate to unmeasurable
>levels. This is not difficult.
I have, and I understand your point. But I've also been working with
enough planted tank beginners for long enough that I have to be realistic.
No matter how carefully you word something, whether in writing or a
lecture, SOME of the people are going to latch on to some (possibly totally
insignificant piece of information) and miss the whole point of what you
are trying to get across.
>> BUT at the same time, I
>> think it's usually safer for beginners to go the laterite/ liquid trace
>> element route, since I ASSUME that most of them will over stock and over
>> feed, under plant and under light.<g>
> If they do all those things, I think they are sunk anyway! Start
>with K and trace elements (I'm not sure what, if anything, laterite does),
>and use nitrate if required. It is not complicated, but one _must_ use
>enough potassium, and I think most don't.
Here, I'm sorry, but you are absolutely wrong. While your method may be
more scientific, and possibly easier if you understand what you are doing,
I _guarantee you_ that there are many people who are fairly clueless, but
are maintaining beautiful, healthy planted tanks that are relatively algae
free using laterite and a good trace element supplement, depending on fish
food/waste as the major source of NPK.
>> Sometimes we forget, here in the list, that by the time someone makes it to
>> this list, whether they seem like "newbies" to the really experienced folks
>> or not, that they are already light years beyond the "average" hobbyist.
> I think the problem is that the subject has been something close
>to a black art for a very long time. "Fertilizers" and other additives
>with unlisted ingredients, lots of conflicting stories about what causes
>what, and an appalling ignorance of basic chemistry have left almost
>everyone in the dark, hoping to find a set of conditions that lets
>them keep a half-way decent looking aquarium.
I have to agree with you completely there.
> It does not have to be like that!
Aquatic Gardeners Association