Do I need to cycle this tank?

[Martin]

Hey guys,

I recently purchased a 20 gallon long and I have been trying to figure out the logistics in setting this tank up if I am actually upgrading from my 10 gallon.  I plan to actually move everything over from my 10 gallon.  I want to move all of the substrate and also the water.  My method for moving the water was to do several serial water changes but to take the water I remove from there and put it in the new tank.  Once the tank is about 25% full, I would do a full move of everything including the water.  Theoretically, this should lead the new tank to be roughly 75% full of "old" tank water and 25% new water to cap it off... essentially at 25% PWC in the end.  Would I need to cycle this tank?  I figure it should be stable from the get-go, but then again, I'm an idiot so...  Any considerations I am neglecting?  Thanks in advance!

Martin

[RyanU]

I would say moving the water over isn't necessary. There really isn't much benefit in terms of bb for the water. One thing I would suggest is to put the gravel from the 10 on top of the extra that you will need to fill the norm of the 20l. I would also move the filter material over as well, even if you just stuff it in there somewhere.  But after that as long as you don't add a bunch more fish you shortly be good to go. I 

[lefty o]

the gravel and decorations, and whatever filtration is what you need to move. put the fish in a bucket of tank water, drain old tank, move substrate/decorations to new tank. fill new tank with water, treat as required. once the temp is within a few degree's of the water they are sitting in, put fish in new tank. after that, just monitor water quality.

[Martin]

Thanks guys!  That simplifies it a lot.  I was thinking the moving the water would be less shock to the fish, but that will make things MUCH simpler.