Dave@AquaFlora wrote:

Hi! Does anyone know what the typical nutrient uptake per day is from
plants? Chuck Gadd's calculator is great for figuring out how much of
what compound to reach target ppms...but if I don't know how quickly
this is being used up then it's either a guessing game or I have to
test the water every day with cheap inaccurate test kits or buy VERY
VERY expensive lab ones.

I did get this calculator
http://www.fwstingrays.com/DosingCalculator.htm ...but it's assuming
daily uptake is 4.5ppm NO3, 1.4ppm PO4, 3.4PPM K, 0.08PPM Fe...is
this average? Also, that calculator gives a lot if
inaccurate/unbelievable suggestions for dosing...since I don't think
all the bugs are worked out---like for my 15 gal it's suggesting 11
ml of KH2PO4 every other day!! If the the calculator worked 100% then
it would be ingenius!

Right now I have 25-30ppm CO2, 2.67wpg, 6Gh, 15 gallon tank wide, 50%
weekly water changes.

Thanks

Dave.

I can't help with the numbers that you seek. They are probably hard to
estimate in any case due to the great variability in plants and sources
of nutrients. Imagine coming up with a good number for iron dose in a
tank with flourite, which initially contains iron but is slowly
depleted.

Tom Barr has shown how to dose accurately without testing, using the
Estimative Index method. It requires large and regular water changes,
which is a problem for some. But since you are already doing them, you
could implement EI with little effort. You can read the details at
www.barrreport.com.

George
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