Re: Poor Man's Dupla Drops

On Wednesday, 13 September 1995, David Whittaker wrote:

> You're very meticulous. I use the mix and K2SO4 in most tanks; however,
> I dose once or twice a week and prefer to keep the two ingredients
> separate. Do you think that there is an advantage to the daily routine?

It's easier for me to remember to fertilize if I feed the fish and the
plants at the same time, and the nutrient concentrations are a little
more stable, but I can't say that there's much difference one way or
another.  I also find it a bit more convenient to pour in a liquid
rather than measure out small quantities of three ingredients.

> The KNO3 is a good idea.

My original mix had just the trace elements and K2SO4.  Then I noticed that
the nitrates had pegged at zero, possibly becoming the limiting factor.

> What bothers me about pond tabs and hydroponic mixes is that the
> phosphate, nitrate, etc. content is given, but the salts that
> deliver the ingredients are not. This might make a difference vis-
> a-vis solubility and possible chemical reactions in the water and
> substrate.

I'd like to know what else is in there too.  The label only accounts for
about 55% of the trace element mix.

> By the way, three cents sounds pretty steep. Someone is ripping you
> off.

I factor in my time at $250/hr.

Actually, the most expensive ingredient is the trace element mix.  My
cost is $15 for 450g.  The cost drops dramatically if you order the
stuff in 50lb bags (but this might earn you a visit from
law-enforcement types wondering just what else you're growing).  The
incredibly cheap amoung us can save even more by forgoing the
distilled H2O, mixing up dry powder and adding it directly to the
tank.  As one reader pointed out, however, powders don't mix well, so
keep the quantities small and shake well before using.  My cardinal tetras
had a habit of eating the powder before it dissolved, and I can't imagine
that being particularly good for them.
Kevin Conlin   kcconlin at cae_ca   "We're Canadians.  We're really cheap"