Moving to a bigger tank

[Dale O Shea]

I have a 66 litre fish tank and im getting a 137 liter pretty soon. im going to use the filter from the 66 in the 137 litre but i just wanted to know should a put the water from the old tank into the new tank or start with all new water and nothing from the old ????

 

[HUKIT]

There really isn't any bactieria in the water, the majority of it's in the filter and substrate. So the most important thing is to switch the filter media and or filter onto the new tank. It you upgrade filters just use the media from the old in the new one for a couple of weeks. This may create a small mini cycle but it shouldnt last more than a couple of days.