I just set up a new 10 gallon tank, and put in a sponge filter (rated for 20 gallons) that's been running in my very mature, established 30g tank for 8 months. I plan to keep it in there permanently.
I added 4 danios from my other tank to this one as a source of very light ammonia to make sure the nitrifying bacteria for nitrates are present. They will be moved back to the 30g and with the rest of their friends once I can confirm there are nitrates.
So in theory, my tank should already be cycled, correct? In your experience, how long did it take to see nitrate in a new tank with a fully seeded filter?
This is my 3rd tank, but 1st time doing a fish-in cycle with seeded media.
Posted by ElephantBanananana
8 Comments
Why put the fish in? Put them back in the other tank until this one is cycled
I would consider it cycled, but would let it run for a week for the beneficial bacteria to spread to the rest of the hardscape in the tank and let the plants establish. Keep the fish in there to keep feeding it ammonia.
Should take a week or less. Test your water
Yes, the tank can be considered cycled based on the filter being already established and the lighter bioload of the aquarium. To speed up the spread of bacteria always recommend to squeeze the established filter in the aquarium to allow the milk and muck( bacteria) to spread throughout the aquarium. This will
Make a mess, but speed up the spread. Add fish lightly until the rest of the surfaces can meet the bioload in the aquarium. Do not remove the fish as it can cause the current cycle to crash if you starve the bacteria of ammonia. You will have some die off.
Stick a frozen shrimp in there to feed the bacteria for a week, works a treat.
The only way to know is to test the water. I would test daily to see if it shows 0 ammonia and 0 nitrites.
I did it that way recently, and have zero issues.
Ran two filters in one aquarium for a while, so I had the extra one to move.
Also moved wood and stones from the old tank to the new (plus around 40% if the water is from the old one).
No problems at all, shrimp and German rams are having a good time (not in the same aquarium).
It’s cycled. As long as the filter is rated for the size tank you have, putting an established filter on a tank means it’s cycled. I’ve done this at least 12 times. I add fish the 3rd day of the new filter running and plants being planted in new tank. Never had any ammonia spikes or nitrate issues. This is the way.