Evaporation during cycling

Smeagol · 03-18-2013, 01:42 AM

How does evaporation affect the ammonia level during cycling? I'm trying to do a fishless cycle in a 20g tank. On day 1, I dosed ammonia up to 4ppm. I'm now on day 8, and I haven't seen any drop in ammonia yet. But water is evaporating.... Should I add more water or just be patient. If I add water, won't that dilute the ammonia, making it appear to have dropped when it really hasn't?

gSTiTcH · 03-18-2013, 02:42 AM

How much is it evaporating?

pelicanincident · 03-18-2013, 05:10 AM

If it has only dropped a few centimeters, no big deal. You can add water if you want. Adding a cm or two of water back into the tank is diluting it by a tiny fraction. If you want to ensure that adding water doesn't give you a false drop in Ammonia, just take a reading of it before and after adding the water. If it drops after adding water, you'll know that you diluted it, and just dose it back up.

genocdex · 03-18-2013, 05:34 AM

when the water evaporates it shouldnt take any ammonia with it. so letting the water evaporate little by little is actually allowing the ammonia to build up. the same amount of ammonia is in the water with less water, thus causing an increase in the ammonia concentration. you should top off your tanks water with dechlorinated water, i wouldnt trust just aging it if thats what your are doing.

lochaber · 03-19-2013, 08:45 AM

Unless your tank is evaporating so quickly that the filter is running dry, it's probably not going to be a significant amount.

The amount of ammonia that would bring 20 gallons of water to 4 ppm, put into 16 gallons of water, would be 5 ppm.

So if you loose about ~1/4 of your tank volume, you'd get about a 1ppm increase.

Were you able to seed the tank with anything from an established tan? (hardscape, substrate, plants, filter media, etc.)

And do you have anything in the tank that may be leaching ammonia (substrate? ferts?)

03-18-2013, 01:42 AM	#1
Smeagol Algae Grower (View User Tanks) PTrader: (0/0%) Join Date: Mar 2013 Location: Ohio Posts: 109	Evaporation during cycling How does evaporation affect the ammonia level during cycling? I'm trying to do a fishless cycle in a 20g tank. On day 1, I dosed ammonia up to 4ppm. I'm now on day 8, and I haven't seen any drop in ammonia yet. But water is evaporating.... Should I add more water or just be patient. If I add water, won't that dilute the ammonia, making it appear to have dropped when it really hasn't? __________________ 20g high, Flourite, 2x24w T5ho, DIY CO2, EI fertz. Otos, Red Wag Platies, Harlequin Rasboras, and lots of plants!

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03-18-2013, 02:42 AM	#2
gSTiTcH Planted Tank Obsessed (View User Tanks) PTrader: (2/100%) Join Date: Feb 2013 Location: Jacksonville, Florida Posts: 312	How much is it evaporating?

03-18-2013, 05:10 AM	#3
pelicanincident Algae Grower (View User Tanks) PTrader: (0/0%) Join Date: Mar 2013 Location: Milwaukee, WI Posts: 64	If it has only dropped a few centimeters, no big deal. You can add water if you want. Adding a cm or two of water back into the tank is diluting it by a tiny fraction. If you want to ensure that adding water doesn't give you a false drop in Ammonia, just take a reading of it before and after adding the water. If it drops after adding water, you'll know that you diluted it, and just dose it back up.

03-18-2013, 05:34 AM	#4
genocdex Algae Grower (View User Tanks) PTrader: (3/100%) Join Date: Jul 2012 Location: Massachusetts Posts: 71	when the water evaporates it shouldnt take any ammonia with it. so letting the water evaporate little by little is actually allowing the ammonia to build up. the same amount of ammonia is in the water with less water, thus causing an increase in the ammonia concentration. you should top off your tanks water with dechlorinated water, i wouldnt trust just aging it if thats what your are doing.

03-19-2013, 08:45 AM	#5
lochaber Planted Tank Enthusiast (View User Tanks) PTrader: (0/0%) Join Date: Jan 2012 Location: Oakland, CA Posts: 734	Unless your tank is evaporating so quickly that the filter is running dry, it's probably not going to be a significant amount. The amount of ammonia that would bring 20 gallons of water to 4 ppm, put into 16 gallons of water, would be 5 ppm. So if you loose about ~1/4 of your tank volume, you'd get about a 1ppm increase. Were you able to seed the tank with anything from an established tan? (hardscape, substrate, plants, filter media, etc.) And do you have anything in the tank that may be leaching ammonia (substrate? ferts?)