Replacing an aquarium with a bigger one
I momentarily have a 110 liter aquarium. I now purchased another one with 240 liters since this one has become too small for me. Now the new one is supposed to be located exactly in the place where the old one is, but the old one is completely stocked with fish etc. And the new one needs to stand for at least a week before I can add fish.
luckily, it is not that bad:
1. Empty the old tank as far as possible, collect and keep the old water (!). Depending on the filter, operate it on a bucket of water as to supply the bacteria sufficiently with oxygen.
2. Carefully push the almost empty tank away along with (!) its cabinet/stand, emptying the space it occupied. This should not be too much of a problem with two strong people that lift and push, plus a third person that removes possible obstacles (e.g. a carpet that bends up in the worst of moments). In case of an even floor (parquet, tiles), it is best to place a small piece of carpet that is not required anymore underneath the burdened edge of the cabinet, upside down. This makes it considerably easier to push the cabinet, and the risk of scratches is considerably reduced.
3. Bring the new tank in position and set it up - you should of course prepare as much in advance as possible, i.e. checking for water proofness finished, rocks washed, plants at hand etc.
4. Fill the new tank with the old water, transfer the fish, connect the filter or fill the old filter material into the new filter, and put it into operation.
5. Top up tank with tempered and conditioned fresh water, switch on heater and light (possibly postpone switching on the lights for a day if the fish are still very frightened).
Dr. Bodo Schnell