Is It Possible?

[Silvani]

I’ve heard that it’s only possible to cycle a tank that is 5 gallons or more. Now is this just because smaller tanks are more unstable, and difficult to cycle, or is it truly impossible to cycle smaller amounts of water?

Right now I’ve been doing 90% water changes on my 2.5 and 3 gallon tanks once a week, and 30% water changes on my 5 and 6 gallon tanks (which are cycled) once a week. If I say started to change out say 50% of the water twice a week instead on the 2.5’s that have whisper filters, would it be possible to cycle them so that I could do 30% water changes?

I really don’t mind if it’s not possible, the amount of time changing the water is the same really. I'm just curious really. I just think that the cycled tanks are a bit more stable, and feel like the bettas in there are more “comfortable” since their water isn’t “new” every week.

Just wondered about the science behind it. I know it’s not totally a betta question, but I figure more people will have smaller tanks in this section than any other.

 

[Synirr]

In my opinion the fluctuations are just too much in small tanks for the bacteria to cope with and this is what makes cycling them so difficult... I do ~70% water changes on my 2.5 gallons with filters without a problem. The bacteria can apparently handle what little ammonia is left, but that's all I'm willing to risk.

 

[Durbkat]

I didn't cycle my 2.5g, I just filled it with water and gravel and waited a few hours for the water to warm up then I put my bettas in it.

 

[tttnjfttt]

I have seen small tanks cycled before. My mom has a 1.5 gallon that she has cycled (more from stupidity and dumb luck, but i won't start on that). Any time I test the water I see no ammonia or nitrite, and plenty of nitrates.

I have also cycled a 1 gal before, but I found that the tank would go into a mini cycle after a good gravel vac.

So I would say the bottom line is it is definately do-able, but if you attempt it, make sure you monitor the water stats, especially for a few days after a water change.

 

[ral]

I tried to cycle four 2.5 gallon tanks earleir this year. Did 3 10-15% changes a week. Lost 3 of the 4 fish in those tanks. I would take Synirr's advice.