On Wed, 4 Apr 2007 15:17:54 CST, Altum
wrote:

The stuff at Walmart generally contains ammonium nitrate. The first
number in the N-P-K fertilizer ratio isn't nitrate, but nitrogen.
Ammonium nitrate is the most common source of it for fertilizer. You
can get away with burying a fertilizer spike with some ammonium nitrate
deep in a pot, but of course you wouldn't want to add ammonium to a pond
with fish. If you find a brand without any ammonium, I'm all ears!

I can't, but didn't know there was such a thing either.

I must say (Because I feel pretty stupid right now.) that I've never
found an ammonia reading in my pond except once some years ago when
the pond crashed (Because I was busy with other things, not due to
fertilizer.) and I started over again. I've used fertilizers that I
didn't think of as containing ammonia, but in small amounts, and in
ignorance. Thanks for pointing that out.

What is the difference in using a mix of bulk potassium nitrate,
potassium phosphate, potassium sulfate? Sounds like potassium comes
with everything and I wonder why, and if it works better?

I use the bulk chemicals because 1) they're wonderfully cheap and 2) I
can tailor the mix to my individual tanks and pond depending on my water
change schedule and fish load.

The nitrate and phosphate have the potassium counterion (K, potash)
because aquatic and pond plants need a lot of it. Potassium is the K in
the N-P-K number. The chemicals are set up avoid adding undesirable
sodium and chloride to the water. Some people don't even need potassium
sulfate when they use potassium nitrate and potassium phosphate. I find
my plants do better with some extra potash so I add the potassium sulfate.

.................................................. .............Cut to
Soft water and Calcium
BTW, people in sof****er areas also add calcium and magnesium to the
fertilizer. My water is hard so I don't worry about it. I doubt it's
too much of a problem in most ponds since everyone tends to add coral
and/or oyster shells to harden the water a little for koi and goldies
anyway.
........................End Cut

I saw mention of algae blooms with water column fertilizers. My 3
half-barrel pond has a LOT of plants and very few fish compared to a
typical formal koi pond - it's practically a veggie filter. LOL! If I
don't fertilize the water, the WH goes reddish, chlorotic, and straggly
and the algae grows like crazy. When I fertilize well, the WH gets lush
and green, the cannas bloom, and algae is much less troublesome.

I would expect a lot more algae bloom problems in systems with more fish
and fewer plants, since there are often traces of ammonia in the water
until it passes through the filter. Ammonia + iron + sunlight = instant
algae.

You have pointed out something I've missed and must be ignored in many
gardening circles, since breaking down ammonia has long been a source
of fertilizer, but it begs the question where do you obtain these bulk
chemicals. I've never looked for them and doubt my gardening center
carries them, but would appreciate your help as to where to look.

Your help is greatly appreciated,

Hal