ammonia levels

[gersheff]

I am doing a fishless cycle on my 10G. Approximately how much ammonia should I put in to get to the 5ppm. I tried doing a few dilution on my own, but nothing seems to be working. I keep getting very high ammonia levels

[JSchmidt]

It's hard to say... there seems to be some variation in the concentration of ammonia available commercially.

For a smallish tank, try 4-6 drops, then test. If it doesn't register, double it and try again. You should be able to creep up to the 4-6 ppm needed for fishless cycling.

Good luck,
Jim

[brendanh]

"PPM" is a very poor unit of measure, desipite its wide use. Most of the time this is a mass/volume measure, but it's never clear. On the test kits, I think it measures mg/L.

If you want 5 ppm NH3 in your tank, let's do a simple calculation.

The density of pure liquid NH3 is 0.682 g/cc, or 682 mg/cc.

10 gallons * 3.7854 L / gallon = ~38 L tank.

38 L * 5 mg NH3/L= 190 mg NH3 in your tank.

Now divide by the density

190 mg / 682 (mg / cc) = 0.2786 cc of pure NH3 in your tank to get to 5 ppm.

Drop size varies, so take some AMMONIA and see how many drops it takes to fill up a teaspoon. Let's say it's 20. Then you have 20 (drops/teaspoon) / 4.928 (mL/teaspoon) = ~ 4 drops/mL.

Now you have 0.2786 mL * 4 drops /mL ~ 1 drop!

This is for pure ammonia. You will have to recalculate if you're using comercially diluted ammonia. Find out the concentration of your ammonia solution. If it's 50%, multiply the number of drops by 2 for a decent approximation.

[happychem]

Originally posted by brendanh
"PPM" is a very poor unit of measure, desipite its wide use.

I agree, but then, so's the entire imperial system:rolleyes:

[gersheff]

thank you. I already put a bit too much in my tank, time to do some serious water changes

[alphabetta]

When I did a fishless cycle on a ten gallon, I used an eydropper and I put in 70 to 80 drops of Great Value brand Clear Ammonia to bring it up to 4 ppm. When I used a more concentrated brand of ammonia, I only put in 30 drops to bring it up to4 ppm. HTH

[brendanh]

It looks as if commercially available ammonia is about 1 M, or 17 mg/mL, very very weak stuff.

At 1 M, you'll need 190 mg / 17 mg/ml = 11 mL or about 2 full teaspoons to get it going.

You can see the huge difference between pure ammonia and this comercially available stuff. It's critical to know the concentration. That's why there's such a wide variety of numbers flying on these forums.

[gersheff]

I am trying to get a hold of the company, with no luck. All i know is that the stuff smells pretty strong.

[gersheff]

Well I just found out. It is Ammonium hydroxide 5%

[brendanh]

Ammonium hydroxide is a liquid about the same density of water. It's actually the same thing as ammonia in water since

NH3 + H20 --> NH40H

So if we use 950 mg/mL as the density, at 5% ammonia we have 47.5 mg/mL of NH3, assuming percent by mass is about the same as percent by volume, since the densities aren't too different.

That's 4 mL of your solution to make the 190 mg you need for 5 ppm. (a little less than 1 tsp).

[gersheff]

why can't you just multiply the previous number by 20

[brendanh]

Well, because the density of liquid ammonia (.68 g/mL) and liquid water (1.00 g/mL) are different. So if the solution is close to pure ammonia, you divide the first number I gave by the %age ammonia in solution (If it's greater than, say 50%).

Otherwise, you have to take the density as closer to water. That's why the numbers are slightly different... about 4 mL vs. 5.5 mL or so.

Anyway, both numbers are pretty close to a teaspoon. So at least you have a rough idea about how much to add.