A year ago upgraded from a 65 gal
. To a 120. Transition was very smooth. First step:
- Gravel vac old tank, then transfer old gravel to new tank, mix old and new gravel.
- Transfer as much old tank water to new tank as possible. Keep power filter running as long
as possible. Keep the media reservoir full of old tank water when the filter is turned off.
- Transfer decor and fish as well as the heater.
- Top off the new tank with dechlorinated water and get the power filter up and running.
If you decide to use the old gravel, a very thorough gravel vac is very important prior to transfer and when you dig it out, be careful not to stir up the gunk. I learned the hard way several years ago during a transfer. The noted gravel gunk caused a big time bacterial outbreak and I lost several prized fish.
I've probably left something important out, maybe someone else will fill in the gaps.