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Re: Ratios K2SO4/KNO3



Susie wrote:

> I'm with Tom Wood:
> 
>> All I really want to know is: At what ratio should KNO3 and K2SO4 be dosed,
>> roughly, by weight, discounting all other inputs to the tank?

Depends on your fish load.
Depends on your overall grow rate
Depends on your plant types
But generally in a low/moderate(this is relative) fish load tank
I add 1/4 teaspoon per 35 gallons of ""water"" of K2SO4 weekly
I add 1/4 teaspoon per 35 gallons of ""water"" of KNO3 after water changes
and 2 times more throughout the remainder of the week(slighty less these
times and with high fish loads/feedings you may need none). Adding at water
change time only is not a bad goal to get to IMO. Then you only add for
water changes and some P (depends too) and Traces(depends on if you use CO2
or not) throughout the week.
Dosing can be a bit like LA's freeway with all the turn offs and on ramps.
Many different ways to go and they will all get you there.

My ratio is NPK---> 5:1:30
I have not done a dry weight roast on my plants but different plants will
have different compositions(even different N species compositions).
I think you will find this rather a fruitless endeavor to find a general
level and try to attempt to base one's additions on this amount.
> 
> I sincerely hope not, it seems to work okay.  Maybe my version of KINO3,
> which is in round globules the size of Osmocote balls, is less
> concentrated?!  Not too many of them fit onto a teaspoon.

This is what I use and most folks I believe have been using. It's relatively
pure KNO3. I tested the brand and took average weights to find the
concentration per 1/4 teaspoon(Flat) in 35 gallons of water. I think it was
about 6.3 ppm of NO3.
We had thought it was more like 5ppm of NO3 but I decided to be anal about
it since so many folks were now using this method and do a good little
averaging and weight test. I ran a large number of sample weight and and a
couple of different teaspoon measures(all teaspoons are not created equal)
to get a good idea of what folks might add. Plus or minus 1ppm is not that
big an issue on NO3 for a plant tank when trying to maintain an effective
""""range"""". I think the weight average was 1.6 grams per 1/4 teaspoon.
You can go back and look in the archives I guess if your really interested
in that part. 

Regards, 
Tom Barr