Re:Nutrients & Hydroponics vs Aquaculture
>After talking to various plant people, it was interesting to note
>that the levels of trace element in the PMDD mix vs. most hydroponic
>trace mixes are 20 to 1,000 times as much. Does anyone know why we
>would need (for example) 1,000 times more of an element in a fishtank
>vs. hydroponics (which seems to me to be the same minus the fish)?
Yes, the product concentration is lower, but the amount (volume) you
actually USE is more. I do not know why the stock solution of some
hydroponic fertilizers is so low (maybe so they can sell more units?).
The actual concentration of N-P-K and trace elements in the hydroponic
growth medium is higher than we would dare have in our tanks.
I inquired about a 7% chelated iron-trace element mix at a hydroponics
store once, and the clerk was astounded--"500 grams of 7% Fe?!?!?!?
Why, that would last you for YEARS!!!!" Another clerk tried to
persuade me that 7% Fe would be toxic.
It's also worth noting that the American hydroponics shops sell mostly
dilute, liquid fertilizers, very little powder. If you work out the
costs, you are paying a pretty penny to have (mostly) water shipped to