Changing Gravel.

[Steffyboy]

Hi guys
 
Bit of advice please.
I've got a 4ft tank that's been going for nearly a year now and would like to change the gravel.
I have the 5-6mm gravel and am looking to swap it for the finer stuff i have in my other 2 tanks.
I know the gravel contains critical bacteria etc and have learned from past mistake when i sculpted hill mounds with it and disturbed the balance which created a cloudy tank for over a week!
What would be the best option for me to replace it with finer gravel?
I know bit by bit is one option but i don't want to get it mixed up.
Would a total swap of gravel in one be the worst mistake i could make?!!
Any help would be appreciated,
Cheers.

 

[copps321]

i will be doing the same (although to sand) i will be just hauling it all out and swapping it over but keeping my filter wet (which is not hard being a canister) i have done it before in old tanks and never had any problems so im just going to do it the same way