Calculate Amount of 10%NH3 for 5ppm?

[mound]

I'm reading this article on fishless cycling:
http://www.cichlid-forum.com/article...ss_cycling.php
and it states:

2nd method. This one is used by probably 99% of hobbyists. Addition of X amount of NH3 drops until Ammonia level of 5ppm is achieved. This X amount of drops has to be added daily until NO2 spike. Afterwards follow up with ½ X (from previous step) amount of NH3 drops daily until NO2 is 0ppm causing NO3 peak. ~50% water change should follow -> cycled tank. (this recipe uses regular Pure Ammonia 4-15%)

I have a 125g tank which I want to cycle in this manner. I have an ammonia solution (no additives) that's 10% NH3. Is there a way to determine how much of this solution I need to add to 125g of water (probably more like 115g with all the rocks) to create a level of 5ppm? I don't have an eyedropper and my guess is that I'm looking more in the order of tablespoons anyway..

[RogerMcAllen]

As a chem major at the U of I I <3 chemistry. Give me a few min and I'll be back to you with an asnwer.

Eh, ppm suck. I came out with 21.750 L, but that seems like a ton. I am probably off by a couple factors of 10. You probably shouln't add that much.

[fishfreek]

HM, Makes our method of the fishless cycle by using some raw seafood to start the cycle a bit less confusing.

I hope Roger can exercise his brain and give you an answer on the number of drops to drip.

[RogerMcAllen]

I will assume that the 10% is by volume, so I reworked it, and that comes out to about 2.18 kg, or 4.8lbs of ammonia. That is something like 2 L of NH3. In gallons that comes to a little over a half.

[mound]

wow - a half a gallon.. that sounds VERY high.. somewhere (I wish I could find it) I seem to remember somebody's post talking about 1/4 cup and it created like 7ppm.. the tank may have been smaller, but even if it were much smaller than my 125g, it wouldn't be that high.. then agian, you're the chem major cranking the numbers..
maybe I'll start with a quarter cup, wait and see and keep adding and then get back to you.. wow, a half a gallon..

HM, Makes our method of the fishless cycle by using some raw seafood to start the cycle a bit less confusing

"HM" ?? anyway.. yeah, I've read about using dead seafood (shrimp) on this site, but... well, there is no but I guess, but using ammonia seems like a more straight-forward approach than waiting for a piece of flesh to decompose

I'll report back how much of the 10% NH3 solution I added to get 5ppm in 125G, meantime, if your figures change again, do tell (oh, and if you could post your calculations, that'd be cool.. just curious how you derive ppm from gallons)

[RogerMcAllen]

Dont' got entirely by my numbers, ppm is not a unit I use a lot. Also conversions get trickey. I may have made mistakes, so you should probably double check other places.

[mound]

ahh I'll just trust your first calculation and dump in 21.75L right away

thanks though, I'll get back with results

[RogerMcAllen]

Sure, here goes.
1gallon=3.785 L
125g = 473L

5 ppm = 5mg/L H20

5mg/L = mlNH3 /473 L

2365.625 mg ~ ml NH3

2.365 g ~ml NH3

2.365 g NH3 is something like 1.57 ml

your solution is 10%, so you need 10x as much, so 15.76 ml
.01576/3.785 =.0041gallons
so about 1.5 pints, or a little under a cup like you said

It works much nicer when I have some numbers to reference off of to make sure my math isn't totally crazy.

*thanks for suggesting I write it all out, I caught some huge math errors that multiplied my old answer by a factor of 100

[mound]

ahh that looks right.. 1.5 pints makes sense, your 2nd solution said 2L (Litres right?)

thanks!
(I should have paid attention in Chem class

[mound]

oh, and a pint is 16oz, and a cup is 8oz, so 1.5pts = 24oz = 3 cups