Upgrading to 6ft USED tank with Sump - When to transfer fish

[steeledr]

I have purchased a 2nd hand tank that has been running for a long time - it has a large sump and all the filter media is included. The new tank is 680 litres and the sump is 180 litres - total 860 litres. My current tank & sump is 220 litres and I will save 240 litres of used water from my current tank from tomorrow and Saturday's water changes. If I transfer the 240 litres PLUS the contents of my old tank ( 220 litres ) to the new tank is a total of 460 litres which means I will need to make up another 400 litres of new water with Prime, pH adjusted etc. IF I transfer the entire contents of my current sump incl. ALL the filter media material, and all the bacteria that can be seen inside on the floor of the sump into the new sump and use Seachem Stability will it be safe to transfer the Discus immediately OR should I set up the new tank first, then add some filter material and sand from the old tank and a few Cardinals and Cory Catfish for a week or two before transferring the Discus to the new tank. I would appreciate some advice?

[Discus Planetarium]

As long as the filter media material is still wet from your old tank and the new tank you should be good to go I know people who have new tank set up NO CYCLE add fish but they do 80% water change every day so I think you will be right to go....

[steeledr]

Yeah the new tank filter media is still wet and transferring my filter material immediately from the old tank to the new tank. I thought it should be ok but wanted to check. Thanks