Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
Sharing media between an established tank and a new set up is a good way to get the cycle started in the new set up. There are a few things to watch out for:
1) Do not take too much from the established tank. This could result in an ammonia spike, so monitor that tank closely, testing for ammonia and nitrite. About 25% of the filter media is usually safe. More is questionable.
2) If you do not take very much media from the established tank then the new tank will not handle a large bio load right away. (perhaps as little as 1/8 of the bio load of the donor tank)
3) Nitrifying bacteria grow slowly. They do not cloud the water. If your new tank has cloudy water it is from some other problem, perhaps heterotrophic bacteria. These are good guys, but not part of the N-cycle. Let it be, it will clear up on its own.
4) N-bacteria need ammonia. If you took the media from the established tank, added it to the new tank, then did not feed the bacteria they start to die off. Not all at once, not instantly, but a couple of days = fewer bacteria, a week with no ammonia = significant die off. You can use ammonia, fish food, a dead shrimp from the grocery store.
5) Best source of nitrifying bacteria that you can buy is in a bottle that is labeled that it contains Nitrospira species of bacteria. Do not waste your money on anything else.
Here is what I would do:
Go get a bottle of Dr. Tim's One and Only or Tetra Safe Start or Microbe Lift's Nite Out II.
Split the cycled media between the 2 tanks according to how much bio load each will have.
Add the bottled bacteria to both tanks.
Add ammonia to the tank with no livestock to feed the bacteria. Test, 1 ppm is good for a planted tank, up to 3 ppm is OK with no plants in the tank.
When the livestock arrives:
Test the water. Have the bacteria removed all the ammonia and nitrite?
Do a really big water change.
If there was a trace of ammonia or nitrite before the water change, then add some more bacteria to the new water.
Then add the livestock.
The bottled bacteria takes a few days to get going.
By adding cycled media there is a big boost in established bacteria in the new tank.
Adding bottled product to the old tank makes up for the bacteria you have taken out of the filter. Adding it to the new tank boosts the population in that tank.
Feeding the bacteria in the new set up encourages it to anchor to the filter media, and to get growing.
But if the new livestock is arriving so quickly you might only be able to add the ammonia once. There might not be enough time for the bacteria to remove it. On the other hand, the established bacteria on the filter media might do the job completely, turning the ammonia in to high nitrate.
So, no matter if there is ammonia or nitrate in the new set up, do a water change before adding the shrimp.
If there was some remaining ammonia, add more bacteria. It cannot be overdosed. You can keep the bottle in the fridge for several months, and use it whenever you need to add N-cycle bacteria to a tank.