Smaller tank = smaller length of time to complete cycle?

We bought our 6 year old a 5 gallon hex for his bedroom and that cycled in under 2 weeks. I would say it was about 11 or 12 days but we had seeded it with gravel from our 75 gallon so I don't know how much if at all that helped.

Our 75 gallon was started new with everything. That bugger took 4 months! Drove us insane.

Our 37 cycled almost instantly because we took a spare filter off the 75 as well as decorations...etc. We had a teeny Nitrite elevation (.25) for a couple days and never saw it again.

Good luck.

Jighead said:

Does a smaller tank, like a 5 gallon take less time to cycle than a larger tank? ... I imagine because the volume of water is a lot less than the cycle would also take less time. Please correct me if i am wrong.

Click to expand...

I'm no expert, but from my understanding of cycling, this would not apply. Half the water does not equal half the cycle time. It's kind of like asking: If I only half fill my dishwasher, will it run in half the time? Nope! Your tank still has to go through the same biological processes to grow the bacteria it needs. There are some variations (small tanks don't have to grow as much bacteria, for instance) but basically you can't make something grow more quickly than nature allows.

However, like ejk0799, I'm a big fan of CHEATING! If you can add bacteria from another tank, cycling is a doddle. Gravel, filter sponges - the tank you steal them from will replace the bacteria quickly, and your new tank will be 'instantly' cycled. I've done three tanks this way (5g, 55g and 86g), and have never had a problem.

Remember: Cycling is about the bacteria, not the water!

csdax is correct. A cycle will not be significantly shorter an a smaller tank.

Seeding is a good idea to "kickstart" your cycling procedure.

The only way I can think this would have an effect would be that if you are doing a fishy cycle and both tanks have the same fish load, then a larger tank might take longer because ammonia/nitrite would take longer to "bump" into the small initial amount of bacteria in the tank. If the concentrations of ammonia/nitrite are the same, then it souldn't matter.

It should take the same time to cycle an unseeded tank regardless of size. However, as I understand it, a large tank with a very small bioload may take longer to start the process of cycling due to little ammonia being produced to encourage the growth of bacteria.

Cycling or the positive ammonia or nitrite readings are concentrations, not volumes. There will be no difference in timing between small or large if you are working with conventrations.

cycle time is based on bioload. cycling is the process by which you supply the good bacteria already found in small quantities in your water with food to grow a large enough colony to handle the bioload in your tank. if you have a very light bioload, it doesn't take as long for the bacteria to build a large enough colony to handle the bioload. if your tank is heavily stocked, it takes longer.