by **philip_la** » Thu Jan 11, 2018 1:41 pm

Thank you, Larry!

Admittedly, I got lost a little bit with your numbers, but you did jump start a few of the old neurons. (I didn't, however, grasp the accounting for the Ca in the math.)

I tried calculating this again and I got *close* to the same solution:

Striving for:

10 mM Ca(NO3)2 = 20 mM NO3

20 mM x 62g/L [molar weight of NO3]= 1240 mg/L of NO3 (the dilution rate to be achieved)

Beginning with the existing solution of "7.5% Nitrate Nitrogen", or 75g/kg...

[This is where I think I was initially messing up as I was calculating based on weight of *nitrate*, and not nitrogen which would imply a much higher concentration.]

1 Mol of N is 14g/L.

The solution weighs 250 g, and contains 235 ml. Doing the conversion to liters, the existing solution of 7.5% is then:

[1kg x 235ml/.250kg = .940L] thus 75 g/940 ml, or approx. 80g/L of Nitrogen. This would equate to about 354 g/L of NO3, (having a higher molecular weight of 62:14)

If I've done math correctly, and made appropriate assumptions thus far (??!) then to dilute a 354g/L solution to a 1.24g/L solution, I would do approx. a 1:285 dilution. THat's roughly 3 1/2 ml/liter. Ultimately, my 8 fl. oz bottle will be good for about 67 liters of finished solution. (I suspect the bat guano will have gone funky long before I use that up!)

I apologize for beating this thing to death, but I don't want to mess this up. I was worried that I might do better to wait for the store to restock, repeat my trip, and exchange this stuff for pure Ca(NO3)2 to avoid the hazards associated with my poor math, but I find consolation in the fact that you and I have now come up with comparable rates of dilution...

I don't know why I assumed ammonia for bat poo. (I think I remembered seeing a show in which some cave explorers were complaining about fumes coming off a pile of the stuff, but I doubt spelunkers took the time to analyze the more nuanced aromas coming from a pile of bat scat.) I'm thinking urea might be less toxic to seedlings?

Thanks again!

Thank you, Larry!

Admittedly, I got lost a little bit with your numbers, but you did jump start a few of the old neurons. (I didn't, however, grasp the accounting for the Ca in the math.)

I tried calculating this again and I got *close* to the same solution:

Striving for:

10 mM Ca(NO3)2 = 20 mM NO3

20 mM x 62g/L [molar weight of NO3]= 1240 mg/L of NO3 (the dilution rate to be achieved)

Beginning with the existing solution of "7.5% Nitrate Nitrogen", or 75g/kg...

[This is where I think I was initially messing up as I was calculating based on weight of *nitrate*, and not nitrogen which would imply a much higher concentration.]

1 Mol of N is 14g/L.

The solution weighs 250 g, and contains 235 ml. Doing the conversion to liters, the existing solution of 7.5% is then:

[1kg x 235ml/.250kg = .940L] thus 75 g/940 ml, or approx. 80g/L of Nitrogen. This would equate to about 354 g/L of NO3, (having a higher molecular weight of 62:14)

If I've done math correctly, and made appropriate assumptions thus far (??!) then to dilute a 354g/L solution to a 1.24g/L solution, I would do approx. a 1:285 dilution. THat's roughly 3 1/2 ml/liter. Ultimately, my 8 fl. oz bottle will be good for about 67 liters of finished solution. (I suspect the bat guano will have gone funky long before I use that up!)

I apologize for beating this thing to death, but I don't want to mess this up. I was worried that I might do better to wait for the store to restock, repeat my trip, and exchange this stuff for pure Ca(NO3)2 to avoid the hazards associated with my poor math, but I find consolation in the fact that you and I have now come up with comparable rates of dilution...

I don't know why I assumed ammonia for bat poo. (I think I remembered seeing a show in which some cave explorers were complaining about fumes coming off a pile of the stuff, but I doubt spelunkers took the time to analyze the more nuanced aromas coming from a pile of bat scat.) I'm thinking urea might be less toxic to seedlings?

Thanks again!