Planted Tank Guru
Join Date: Jul 2010
Location: Huntington Beach, CA, USA
The three weeks away is a problem but I would assume that you will have someone checking things while you are gone. If not there may be a major problem with the tank at best. If not the temperature, there is a good chance of other problems. The tank will suffer in some way while it is not watched. Long vacations and fishkeeping are not really compatible. If one had any other type pet, the situation might be even worse.